Denny - I have a handful of the right size in stainless along with stainless washers, lock washers and nuts. I'll be powdercoating the brackets, simply because I have the extra black powder and the tools to do so, and eventually coating the frame with POR15 or similar so I'd hate to have a set of rusty bolts ugly up my purdy work.
FriedGreenTmater - The rear brackets angle down in the middle. These are good examples of where it should sit. In the second one you can really see the angle in the bracket.
http://farm8.staticflickr.com/7419/9219955748_4ca8434421_b.jpghttp://farm4.staticflickr.com/3824/9217203391_8b6c21fe35_b.jpg 
