Lol Mark
Caltrain already functions much differently than most "commuter rail," and with the frequencies increasing it will basically be a metro-type service.
I think the night-time service is kind of a chicken/egg thing - as soon as frequencies are increased during the day, more people will begin to ride and depend on Caltrain, which will increase calls for night service, etc.
I would be absolutely shocked to see Caltrain go to every ten minute service during most of the day and not add some night service somewhere along the lines of what BART has.