I love the PRT concept. It's like a compromise between buses, gondolas, and elevated rail. It's plainly more flexible and modular than rail, far more efficient than buses, and faster than gondolas. As far as I can see, it looks like the best of all possible solutions, especially because it relieves traffic without interfering with ground-level transit.
If only Garriott were as rich as Warren Buffet, he'd be like a cross between Elon Musk and Paul Allen --- big, flashy, fun, innovative tech on a grand scale. Seems like Musk or Allen would be suitable investors for a project like this, although Allen is so partial to Seattle that he'd want it built there instead.
Speaking of Seattle and PRT, here's some PRT number crunching as applied to Seattle by an advocacy group there:
http://kinetic.seattle.wa.us/nxtlevel/prt/capacity.html
And here's a video of a PRT system that is in use at London's Heathrow airport:
https://www.youtube.com/watch?v=_rFvoxMTS4Y
I would think it could be a lot faster without sacrificing safety.