Hmmm, Magnisium!
Wouldn't the bike be lighter with nothing at all?
Perhaps I'll start making paper mache covers and paint them black, could be a good market out there.
But of course for some I'll have to drill holes in the paper
Nope, they're genuinely that freaking expensive when they're in good shape - spent ages watching multiple sets go for silly money on Yahoo auctions. The Yoshimura Mag cam cover caps are highly desireable - both for real kats, and GSX400 impulse.
More wank factor than performance boost, though. A good poo before you ride would probably offer a similar weight saving. :?
Lets face it, most things people spend money on are wank factor.