A lot of people have. Go take a look at tonymacx86.com for instance.
You can build Macs with ATX boards? Can you use an ASUS with a duel video and dual video cards?
What do you need? I know they had Macs running on Dells but they were very tricky. What O/S does yours use, does it matter? Is the performance the sane? Awesome!
I’d love t do this, say you mind if I pick your mind???
I’d love to have a Mac that was at a decent buy plus I could build it myself!