Lol i think it's a funny idea, people would be too controlling over who does what. Maybe two or three people building a directory would work, but with 100's i think it'd be abit confusing heh
You would do better to get 5 investors together and put in $2k each and get a directory script coded and then promote it and have a free version. The link backs would get your site a PR6 probably within a year and you could make some serious cash.
Really a Great idea... But 100 people practically working online is very tough.. So better take 5-10 dedicated people who wish to work.. & then u can see ur goal of PR8 a SUCCESS
And then google comes along and takes away PR as its a load of shite. Be great to take on dmoz though as it appears to be run by a bunch of commies.