Since edge grain is an option as testified with DC's latest bow, has anyone tried flipping a bow around and using the belly grain as the back? I've thought about it, and here's why I think it might be a good idea. 1) pin knots and other imperfections on the back won't usually carry over to the belly of a stave if you start deep enough. Therefore, as long as the stave is deep enough into the belly wood after getting it wide enough you can almost always get a clean back, that is if you can follow a concave growth ring. 2) a while back someone made a bow with a hollowed out back to counteract the Poisson effect. This supposedly increases tensile strength or something (like what you see on tape measures). What if instead of hallowing out the back you use the belly's natural concavity?
The downside to using the belly of a stave as a bow's back could be that it's harder to follow a growth ring (considering it's concave shape). You also might have to take quite a bit of material off to get past splitting damage, and to get it wide enough. It also may not work well if the stave is too thin that you have sapwood on the belly. Maybe it depends on the species, but I imagine sapwood isn't as good in compression as heart wood. But then again I see many sapwood only bows on here with the only heart wood being in the handle.