ISO: BYOB with private room for a small wedding reception
Any suggestions in Philadelphia or the immediate surrounding suburbs would be appreciated (20-30 guests max).
I had my rehearsal dinner of about 32 people at Sabrina's and everything was stellar. The food was actually better for that dinner than I've had there since. They put our group in the dining room on the west side of the restaurant, it was a little tight for 32 but should be great for 20-30. There's no room for dancing, of course, but since you're asking for a BYO I'm guessing that's not on the menu.
A colleague had her rehearsal dinner at Marigold Kitchen and said it was terrific. I think they have private rooms - not sure how many they hold.
You should look into Little Fish at 6th and Catherine. Been there twice in the last 2 months, food is supurb and I know they do private parties. I would say they can seat up to 30 people.