Made a new thread for this subject.

We've have people talk about using OpenBazaar for this type of thing
before. Simon de la Rouviere wrote about replacing Uber with an OB based
system a while back:

http://simondlr.com/post/88070070168/the-blueprints-for-a-decentralized-uber

I've seen a number of detailed comments proposing systems like this
before on Reddit, I'll see if I can dig them up.