Here is a hack I did back in 2004. I was cleaning up my external HDD when I ran across these pics. Then came the Oh Yea moment.

If i remember correctly, I used the original power supply and monitor circuitry, but I used an ATX power supply to power the small pentium 3 900Mhz intel board. The internal monitor would only do 800x600. it wouldnt do any more than that.

Eventually the plastics cracked and got all messed up, so i stripped it all down. Plus I used the CRT to replace the bad one in my G3 AIO and it worked fine.