Epoxy granite is all very well, but for 1% of the hassle I can go to a nearby stone mason and buy a tombstone blank already polished up and pretty flat.
Well, why not?

Yes, there are quite a few threads here about sitting a steel or aluminium frame on top of a granite surface plate, but that is not what I mean. I am asking about using a granite tombstone slab as the actual base for some heavy linear bearing rails. Maybe using more granite slabs as the uprights for a YZ gantry. (Or beyond that.)

If this has been discussed before, just point me in the right direction please.
If there are some commercial machines which already do this ... I know there are, but feel free to mention them.

Cheers
Roger