"Any Beige G3 can be readily upgraded to a 400-500MHz G3 via a ZIF processor transplant from a Blue and White"

I do not believe this is correct. The Blue and White has a 100mhz bus speed, the beige is only 66mhz. There will be issues if you try to swap newer CPU's into the older machines. Also, there were no 500mhz B&W's. 450mhz was as high as they went.