C hubs haven't been an issue.. I had Alum ones made about a year and a half ago in both 4 and 6 degrees.
That's cool, but the added stress on the arm, hinge pin, and hinge pin mounts would seem to cause more trouble (broken arms, tweaked chassis) than some cheap hubs. Very cool nonetheless, where'd you pick them up at? i know dynamite had aluminum hubs for the xxx-s, but that's about it.