I like the idea of a revival of the Lark as much as anyone here, but is there really a market for that kind of service anymore? We're basically talking about a point-to-point service (let's face it, there's not going to be any business between intermediate stops from Santa Barbara - Paso Robles: too few people, and it's the middle of the night). By way of comparison, how is that overnight sleeper bus doing? If people are using it, then that could indicate there's demand that warrants further study. If not, well, then interesting idea but that's it.

An overnight LA-SF/Sacto service that might merit some study would be the San Joaquin Valley line. There, you actually do have a population base, e.g. Bakersfield at 365,000 people vs. SLO at 45,000 that could generate business between intermediate stops. A train leaving LA at around 6:00 in the evening would reach Bakersfield before midnight; the return trip could be scheduled to leave the SF Bay area around 9:30 PM, with an early AM arrival in Bakersfield and late AM to LA. Basically, the Owl's old schedule.

Of course, there would be issues with the host railroads and track capacity, especially over Tehachapi, and Uncle Pete would want nothing to do with this. But it's fun to spitball anyway.

One last thought: I scratch my head sometimes that no one, either pre-Amtrak or since ever tried the idea of a through SF Bay area - Las Vegas service. Point to point it would be around 12 hours and very few would ride the entire length of the trip. But I'd bet there are plenty of people who go from Fresno and Bakersfield to Vegas, and the train would be an attractive option.