The Rotor Bones components are awesome. But they are limited by some of the very things that make them awesome. The snap together construction, and the light weight board, does not handle the stresses that a larger motor puts on them. They get a bad case of fatal shakes if you try using anything much over the 380 motors they recommend.
I wish Chad could find a reasonably priced supplier for the rotor bones design to be milled from aluminum.