It's possible to do. I know there are companies like
Sharp Concepts that use diamond plate aluminium, but I'm a bit sceptical as to the effect on tone. According to both Jason Lollar and Bill Lawrence, you shouldn't get aluminium too close to your pickups because it introduces eddy currents in the pickups, I know for sure that the aluminium pickguard shields Fender used in the 60's make a difference in tone and they are relatively thin.
It also depends on your guitar pickups - Strat and other pickups are suspend from the pickguard, and the microphony of the pickup tends to pick up more of the pickguard tone than you realise. I once fitted a 1mm thick, non-magnetic stainless PG to a Strat that had very microphonic pickups and it immediately turned into something that sounded more like an electric dobro than an electric guitar.