Sorry for not seeing this sooner.
As far as editing the aluminum, try anodizing. This guy has a great guide on it- <http://www.focuser.com/atm/anodize/anodize.html> You'd have to take out all the components first, and perhaps to be effective remove Apple's expensive super-tech surface coating... maybe that's a good thing.
On the side of wood, it would be very easy if you're patient with it. You'd need a good thin-bladed inlayer's or jig saw with a VERY small blade and a drill bit slightly larger than the blade and a nice fine-toothed file. You could make the wood as thick or as thin as you'd like, but if you make it too thin (perhaps less than 1/32") your constant typing will eventually rip it to pieces. As far as gluing it, I'm not sure what to tell you, probably superglue is a safe option but you'd have to make very thin lines in-between the keys. Good luck!

-Knife