Whoa, I never even thought to ask a taxi driver about after-hours bars, but we were in the backseat loudly discussing whether W would still be open and whether any of us knew exactly where it was, and the driver said very coolly, "Yeah, they're open, I can take you there." Cab drivers know everything!
(We had to make a stop at someone's house first, and he even gave us his card so we could call him to take us there when we decided to go--awesome!)