Ha ha another Strike victim why am I not surprised.?? . . . . Search the forum and you'll have plenty of evidence to show the magistrate.!

Anyway back to cutting stone.!. . . I've cut stone on my machine which mainly cuts aluminium. Cut with a diamond encrusted bit and it was easy BUT very very messy with loads of water and slurry coming off and so for this reason I gave up has it was clear that the slurry/water mix was acting like grinding paste and would shorten machine life very quickly.

So my advise is build very strong and design in such away that the linear components are out the way and well protected.! To me stone machines are best purpose built just for that operation.
My friend is a stone mason and the machines he uses to cut and polish stone uses relatively slow running motor with adaptors for purpose designed tooling. This tooling tends to be quite large and often designed for purpose built spindles so it's not easy to interchange with milling or routing tooling.

If you do build a duel purpose machine then I'd certainly look to have twin head with both types of spindle.