A large, thick, slab of anything is going to have some heft to it. I've worked with 1" thick pieces of aluminum (I was a machinist for a while), and I can tell you two things for sure.

1. A solid piece of aluminum the same size as a Strat body is going to be seriously heavy! :eek:

2. An aluminum guitar body is going to a have some sharply-defined resonnances that will make it squeal like a stuck pig! :eek:

Fender has done some interesting things over the years, like the expetimental 1-of granite-bodied Strat. Now that was a heavy guitar! It had amazing sustain, but it needed a special stand to hold it up.

Aluminum guitar body? It would make some interesting sounds, but I'm not sure you could call it musical. :rolleyes: