Grover,
I'm taking overall student budget (including tuition, fees, room & board, etc) into account. So yes, even with San Fran's tremendous living expenses UCSF ends up being cheaper for me. (As a side note, rents in SF are dropping pretty drastically). I'm an out-of-state student for both Pitt and UCSF, although it is easy to become in-state at UCSF after one year. Your situation may not be identical to mine, but I suspect that even with the full tuition scholarship to Pitt the two schools will be at least close in overall cost.
As for the UCSF scholarship, I actually found out after my acceptance but before my financial aid package. It's administered by the admissions office. It couldn't hurt to ask the financial aid office to try to help at all, but in my experience they are pretty much glued to the state budget and their financial need "formula." They say that, historically, they've always been able to meet financial need with at least 25% in grants.
Hope this helps!