Interesting discussion so far, can I add one other idea? I've always thought that some sort of frequent Auto-Train between the Bay Area and SoCal could be a real winner. Not 1 train a day as current running over on the east coast but multiple frequencies, up to hourly even, with multiple destinations. In the north Sacramento area and a couple of Bay Area terminals and likewise for SoCal. That also implies building a dedicated line the same as HSR but since its not as 'sexy' as 220mph trains it probably would be very hard to sell to the public to get it funded. But I still think the ridership potential would be as much or more than HSR.

Just a thought....