I have done some research on p2p bitcoin exchanges. As far as I understand, the project of this topic does not have any code yet. There's another p2p exchange project which does have code: DarkExchange (https://bitcointalk.org/index.php?topic=27055.140
). However it's running into troubles and they haven't figured out yet that coloring is the solution. Actually the bitcoinx project did find that out, AND it has code AND it has a website. I've discussed matters with user "ConceptPending" and it looks like we're joining the bitcoinx project. I'm sorry if I'm stealing away people now, but at least you should be aware of similar projects.
I believe bitcoinx is part of the solution but not the entire solution. Some people are critisizing the coloring of bitcoins in large scale.
My idea: we need to create a IOUcoin in the end where bitcoinx colors the IOUcoin, the IOUcoin will always be worth zero, but the IOU contained may be worth 1 cent or 1 billion dollars depending on what the IOU states. IOUcoin will therefore be inflationary so its value always will be zero, or at least close to zero (like paper you buy to sign contracts, the paper and the ink to sign the paper might cost you a couple of cent but not more)