Just got an email from Rockstar Games. No details as of yet, but it lends credence to the idea of a "Streets Of San Francisco" themed 70s setting, perhaps. It's slated to show up in October 2004 on the PS2.
[Doctors and Bartenders], We both get the same two kinds of customers
— the living and the dying.
— Dr. Boyce, “The Menagerie” (“The Cage”), stardate unknown