My favourite guitar shop ever has a Kramer with an aluminum neck that I've wanted to play for ages, but the owner (despite being a friend of mine) refuses to let anybody play it, and it's not for sale. I've heard that they give out some pretty bright tone, and the sustain... well, the neck's literally made out of fucking metal, of course it'll sustain. Downside: you are probably going to have absurd amounts of radio interference. Have fun with that.
Oh, and I posted about it in the Blog Thread, but I thought I would mention here that I am about $250 away from having a Fender American Vintage Jaguar in my hands. I'm thinking I'll get it in Olympic White, because the natural wear that will inevitably occur over the years will show through so much easier with such a light finish, and a well-worn Fender is like a well-worn pair of jeans. The wear patterns are similar, but none are ever the same, and they are always sexy.