I did indeed do it.
I removed the inner walls and got them welded, Fatmike kept the walls inplace and ran bolts though it, solves all the problems of heat, but is heavier.
I dont think its really worth doing, not when the new echo rim is comming out, 48mm wide and supost to be as hard as alex rims, so should hold grinds better than current wide rims.
I also used a sun doublewide, they are pretty decent, holds grinds really well, but the angled braking suface can be a pain for setting pads up with, I also flat spotted mine really easily, but it did have big holes in it.