It would depend on what part of the country you live, although there are big machines every where they are where you might not expect that is not very big of an area to machine EG is no good for rail mounting would be ok for table leveling
Because of your design you would have a hard job of finding a Grinder that could Grind the table but could Grind the 2 outside rails it all could be machined though, you would have to stress relieve it before any machining, the bottom needs its mounting pads machined as well then it would sit on the machined pads to do the top