I am a big fan of Dogs in the Vineyard and of Stephen King's Dark Tower series.  I keep thinking that these two were made for each other.  They share many of the same themes.  Most obviously is the role of the Gunslingers in the Tower books, just like the Dogs they are wandering peacekeepers who are responsible to the White.  Next is the town as the major setting for each adventure.  There is also the fact that demonic influences are real in both settings.

    There are a few changes that would need to be made I think to make the two mesh better.  First is that in the Dark Tower series the good guys can have access to some times very powerful mystical powers that don't really fit in a Dogs game.  The next problem is that there needs to be some consideration given to how to handle an entire town fighting against the Gunslingers and how to use the raise and see mechanic to simulate a massive combat.  Related to that would be how to handle combats against things that cannot be killed only survived.  There may be others that I have not yet thought of but they are where I want to start.

    I would appreciate any help I can get on this from the community.  I will post with a few of my ideas on how to tackle these issues later as I get the time.  If anyone knows of any resources that might help I would love to see them.

This topic comes up every once in a while. I've read only the first book, and I don't remember it all that well, so, um, don't look at me. Anybody?

-Vincent

Actually, I haven't read the books at all - and this might be why - but I wonder about your reasons for needing the rules you mention. Cause, it doesn't sound like anything the system wouldn't handle as it is. It usually boils down to what the conflicts are about and how you narrate your Raises and Sees. Often, the only thing that needs any actual change when one adapts DitV to another setting is sin progression/demonic influence and the meaning and elements of Ceremony.

You might want to check out this thread for some general discussion about hacking Dogs.

Vincent:
    I don’t know how much time you have to devote to reading but may I recommend picking up the fourth volume of the series “Wizard and Glass” on audio book.  Most of the book is Roland telling about his youth and really allows you to feel for him as a character.  It also has an excellent forward that explains what is going on in the story with out spoiling the rest of the story.  The man who reads the book is an excellent voice actor and I recommend to anyone who wants to read the series that they start with four before going back to the beginning.

Filip Luszczyk:
    Thanks Filip I will certainly check out that thread and you are right in what you said about needing a different scale for the sin progression and demonic influence.  The series has a lot of references to the idea that the king is the land and it often uses the availability and scarcity of water to reflect the spiritual condition of the people living there.  I have been toying with several ideas that would allow me to pull on that element of the story but nothing concrete yet. 
    In the books demons can be both possessing spirits and physical things but both are generally tied to either a specific location or a specific person and have little power to affect things beyond that place or person.  There is also another side that works against the characters in the Tower series and that is the outer chaos and I am wondering how to make that work.
    Also there is a form of magic or telepathy in the stories called the Touch.  In the books the characters with out it harming them can use this power.  Even if the rules in DitV allow for that (which I can't seem remember [our group's GM owns the book]) I think that there is a need to explain what this force is and how it should be treated in the game.  Allow of what I am trying to do is to make this as easily accessible to fans of the Dark Tower and fans of DitV as I can.
    If I have my facts wrong about something please let me know.  I am planning on getting my own copy of DitV as soon as Christmas is over.  Until then I will keep bugging my GM to borrow it. 

I've considered the same thing. Actually, a friend of mine made me start reading the Dark Tower books partially because he thought that DitV would be a perfect system to run gunslingers at the height of Gilead's power, pre Good Man.

Lord Asteroth:
    I hadn't even thought about that.  Setting the game before the the fall of Gilead would be an interesting choice and I may want to include a section on what life was like during that period.  It might also be interesting to play as Arthur's knights fighting to form the Affiliation.

Well, I also don't know the series and like others might be committing the sin of great misunderstanding in this response - and I'll also have responses as to my own suggestions might just not  be good below....

But I think a lot of people forget how flexible Traits and narration (it might be a small "n" but it sure drives Conflicts) are.  A Gunslinger can just say "I invoke the White Power and it raises my opponent into the sky and they burn in a fiery conflagration!"  Even if they do NOT have any Trait.  They just can, because they're Gunslingers, right?  The dice mechanics are what enforce the actual win/lose proposition, narration is (thankfully!) independent of that.  Put another way, SFX are completely separate from mechanics - so you can do whatever you like.  Also, you can have Traits however you want them to be, so you can design Traits - but only if you want - for things like "Power of the White." 

So using this, a massive combat is using a crowd and/or a Sorcerer against the Gunslingers, with Raises like, "Three hundred men advance on you with torches and sticks!" or "The bulidings around you explode!"

If your group knows the literature, it shouldn't be much trouble at all.  If they don't, I grant that makes it more difficult and you as GM need to spell out how to help with this, what the setting is like, etc. - much as the Dogs in the Vineyard book does for its setting.

All that said, this could be all wrong if you have things that need to be mechanically enforced/replicated in order to impart either themes in the book not in Dogs or just to get that special feel of the setting that somehow isn't in what I've described . For example, I think based on your description "the White" has some special rules in order to use its power, in terms of purity of the user or such.  While it's quite okay for your group and you to simply negotiate/discuss if it's appropriate for a Gunslinger to do something if they've been "bad" (to put it overly-simply), Dogs is against any strict regulation of what is appropriate for a Dog (in this case Gunslinger) to do or not do, the game is expressly opposed, so to speak, against any mechanics or overt regulation of what a Dog decides is appropriate - in fact the game is ABOUT a Dog's unconstrained decisions (not to say that "unconstrained" means they can't meet the Conflicts of other Dogs).  Of course one's fellow Gunslingers can take a Gunslinger to task for using the White when they shouldn't.  But if you want/need/require that when a Gunslinger does things he loses abilities and that the GM or some other body will make this declaration "against" a player's decision-making (note I said "player" not "PC"), then Dogs as is does need to be reworked (or scrapped).

Also, your suggestion of the powers not "fitting" makes me think you want an absolute "trump" card when White power is used.  Again, Dogs doesn't do this.  As we've adapted the core engine to superhero play and a player is used to HERO as a system, he say she misses those "absolutes," and it's true, Dogs' mechanical Conflict style deliberately doesn't allow this.  I think it's a good thing, as the old-fashioned "here's a trump-all ability" leads to de-protagonization and/or manipulation of the game to the point it's not really so much of a game.  But I'm not saying it's wrong to pursue this path, just that it doesn't it Dogs.  You could add some things such as chips or d20s or the like that allow for a necessarily-successful or additional power in a Raise, respectively, but beware of how that will interact with the Conflict rhythm/balance.

In any case, best of luck!

There is alot of flexability in the Dogs system but it needs to be focused in order to do justice to the Dark Tower source material.  I realy want to reach both those who have never played Dogs but have read the Tower and those who like Dogs but never read the Tower.  In order to acheive that goal there is a lot of flavor that needs to be added.