If you are looking for a rack for a road bike with no bosses, this one might work for you http://www.modernbike.com/itemgroup.asp?IGPK=2126178270 This one attaches via the rear skewers and the rear brake bolt. This rack only works with panniers not trunk bags. Bontrager has one also for about twice the price. I have looked at these, but never actually bought one.

Hope this helps,

P2