Well, I am thinking it would have to be done with single family housing units like this...
http://forums.pelicanparts.com/showthread.php?threadid=225080
...so as to avoid some of the problems associated with high density housing. I just dropped an email to my property manager to see how he feels about the idea (oh yeah, I don't interact with my tenants. I have a property manager who deals with them). I'm feeling even more skeptical after reading the replies on this thread. I see a Catch22 here...I'd definitely be motivated to provide high quality housing to folks in tough circumstances. But I fear that idea would not be profitable. How much does Section8 pay? Oh yeah, and dtw is right, can you screen out the scary guy with the needle sticking out of his arm and instead select the elderly nice lady who needs a first floor unit for her walker?