Hi, thanks for the input. I had not considered making the machine from solid aluminum. Alas, I already have the granite slabs ready for cutting. I'm currently looking around at different threaded inserts for the granite, and I'm sure drilling and tapping would have been much easier in solid aluminum.
I haven't seen a solid aluminum machine and frankly the thought hadn't even occurred to me. I'd love to see an example.
Some things I'm happy about with the granite is their precision surfaces, and low expansion with changes in temperature.
Honestly I should look around locally for the costs on precision machining just to get an idea, but I was kind of put off by some people's experiences with high costs and then the machining precision is only as good as the machine that does it. I saw one example where they got the machining done but it had a valley midway through its travels.