Here is a draft for the setting info for the All's quiet... thieving rpg.  Although it is setting material (flavor text, etc.) there are also guidelines for role-playing in this world --not rules per se, but descriptions that I think set the mood adequately enough.  Also included is the thieves tools lists, moved to this booklet.

http://www.orbit-rpg.com/Alls_Debris.pdf

P.S.
The Thieves Alphabet will be unique to each game group as it is to be hand drawn by the Thief Players --those are just place holders with the descriptions of your symbols.
I am going to add extra blank place holders without descriptions in a later draft.

I like the thief alphabet.  Did you get the idea from wardriving or hobo signs?  I like the color.  You seem to have researched this pretty thoroughly.

Thank you, Mutex.  What is "wardriving" ?    I've seen educational tv-shows about hobo signs, but I have not researched anything!  I just thought it would be neato flavor for the setting, plus I can envision this played for LARPing too.

Wardriving is when people go about in their cars with a wi-fi receiver, a portable computer (eg., laptop), and sniff out unprotected wi-fi hotspots.  It's taken from wardialing, which was an old practice of having your modem dial huge lists of telephone numbers to try to find unprotected access points.

In early wardriving, the wardrivers would actually mark unprotected access points with chalk symbols.  Now, they probably use a Google maps mash-up.