Emeryville kind of does this, but isn't ideally positioned
Emeryville had great potential, I think the location is great, but as you mention, for getting to SF or SV the public transit sucks. And is alas pretty-unwalkable, even locally. If San Pablo had a Bart Stop (without the 1-3 mile walk to it), it would be much more interesting place, IMHO.
Emery-go-round made up (slightly) for the BART situation. Still not great, though, and it got a lot worse in the past year.
Also, the bordering areas of Berkeley and Oakland are sufficiently bad that I feel uncomfortable at night in some parts of Emeryville. I don't know how you could really set up a separate city without some kind of natural border like the water or hills.
yeah, i should caveat the location is great strategically, in the sense that it is well placed on the map and in (close to Sf/soma, Cal, the Water, 580, weather, etc). in terms human geography/sociology, it has some drawbacks that go beyond the transit issues.
Emeryville had great potential, I think the location is great, but as you mention, for getting to SF or SV the public transit sucks. And is alas pretty-unwalkable, even locally. If San Pablo had a Bart Stop (without the 1-3 mile walk to it), it would be much more interesting place, IMHO.