"Would it be economically viable to provide a paid shuttle service to and from SF / Berkeley / Oakland?"
Perhaps Uber should move from providing premium taxi-like service, and instead offer a 24-hour bus-like service? For partygoers on the weekend, at least?
I think you could definitely be selective in the routes and hours you would operate - I like the idea of charging $20 per person and transporting 50-100 people at a time from major downtown centers (e.g. Civic Center to Downtown Berkeley)
Perhaps Uber should move from providing premium taxi-like service, and instead offer a 24-hour bus-like service? For partygoers on the weekend, at least?