i'd be worried about the carbon disc separating from the crankarm, not the crankarms themselves breaking. i've seen rivetted cranks/spiders separate, and i can't imagine that whatever bond they've made between the carbon and aluminum could be that much stronger, or hold up to the forces of riding a track bike on the street any better.

besides, sugino75 cranks are cheaper. they're not black, but you can get black rings for 'em...