While I'm certain that we could make arrangements to exchange bitbay for envelopes full of USD , what will it take to make bitbay accessible to/from my bank account or credit card? It's difficult to move USD around. Look at coinbase. You need full ID and a bank account that will accept transfers in and out from them specifically.  If you further ID with a VISA card, they'll front you the BTC on demand.

Where will that interface exist? Who will you have to trust to have access to your USD bank account for an exchange between USD and BAY to take place? I'm not sure I'd be willing to open my USD bank account and supply personal information as part of getting an account at bittrex or any other altcoin exchange.

I'm just not sure how any of that would work. There's a place where crypto addresses and real money get exchanged, like coinbase or circle, but who will be handling that exchange between bay and $$?