That's a brilliant icea! There's a huge wedding venue here in Baltimore I can probably contact as the time to brew this draws close.
I'd just start making mass quantities of Apfelwein. Easy to make and it ages very well. In 5 years you could have made enough to provide kegs for the whole night if you did that. I realize it isn't beer but hell, you still made it.
If they're charging for the event, you might run into a little problem serving your homebrew there, even if you're not charging for it...
Better to be safe and review your state's laws regarding it. Could get pretty expensive and even freedom limiting...
Not to be a party pooper, but felt it needed to be put out there...