I have done a few wedding shows, I do mini cupcakes instead of cutting a cake. More baking time, but it's worth it for the 'cute factor', lol. There has always been multiple cake vendors, and usually I am the only one doing minis.
Definitely do more than one flavour! I always do 3, a vanilla, a chocolate and a something a bit 'funkier'.
I don't restrict samples, my first show I ran out in an hour, that was a bit embarrassing. So now I make sure I take plenty.
I just have business cards, 4 dummy cakes on a tall shelf/counter behind me and the cupcakes lined up on the table in front, and a banner that hangs off the front of the table. In my experience, the less I have out the easier it goes, and It looks nicer, which always attracts people.
You want people to take pictures! It's something extra for them to remember you by, putting the business cards in front of them isn't a bad idea.