actually, buffing and sanding wont get you a mirror finish on the aluminum parts, not without a ton of work. See, the outter surface that looks brushed, is coated. I'm not entirely sure what the coating is made of, but if you take a die grinder with a sanding pad to it, it'll come off and leave the bare metal underneath. G5 cases are the same way.

Probably the easiest thing to do would be to chrome paint it. Alsa Corp. who makes some of the more exotic finishes out there makes a product called mirrachrome.

In the near future, I plan to test this stuff out on an iBook. It may be the better way to go.
Electricity tastes good. No, seriously.