Rob Domaschuk , Jul 06, 2009; 05:55 p.m.
A backdrop and stand is pretty common to allow guests to take pictures of themselves against. But that's at the reception.
As for the "formals", I've seen (but don't use) things like (faux) marble benches and columns - especially outside in parks.
If the couple is asking about them, then they likely have something in mind - have they given you any ideas about what they are looking for?