You should try to find backplates for the 1156. We're in real trouble if 1366 backplates are still not available. I am really thinking about a Corsair H50 but they don't have 1156 support. There are only a few that offer support. It sucks.
Good luck, sorry I can't help but my guess is if you looked hard enough, you could find one for the 1366. The 120 is a very popular cooler.