Not sure where you get that p2p services is mostly illegal everywhere. I mean, Uber/Lyft DO exist (though they've been fighting a lot of legal battles, which is good since it brings awareness to the p2p scene). There's Airbnb, which is also legal. Then there's all the other stuff which has cropped up after Uber, like EatWith.com (the uber for food).
I'm super interested in the p2p space and may want to contribute/build apps for it. Do get in touch with me if you are, too.
I mentioned this before, and I'll keep mentioning it, but it seems like what we need is the backbone for all these p2p applications. It doesn't make sense for each application developer to start from scratch, since there would be an overlap. Perhaps we need a single "hub" app for all p2p apps, such that developers can "plug in" their own code. The core "hub" would provide the user's profile, ratings (using a web of trust), etc. It'd be best to reuse whatever possible. Perhaps this could be a further extension of a facebook-like social media app. Not sure to be honest--there's a lot to think about!