So, in real simple terms, what is the motive to create a P2P exchange?
The biggest bottlenecks right now are banks and payment processor. Recent events are good evidence of that (paxum, tradehill getting ripped off, banks freezing accounts without notice). If we rely on Dwolla, then there is still a central point of failure and it may reverse transactions (See there TOS).

I appreciate your work and your thoughts, but in my opinion, it appears to me you are trying to cut out the wrong man first (the exchange).
Figure out a way to do away with the banks and then you are talking seriously cool disruptive technology.