Not only that, but you've got to think about AFTER you've got it all wired up and stuff. Think of the size of the hinges you're gonna need to use. I promise you they all look like ass around that size. Looks like gate hardware.
Here's a better less costly idea. Get the wife/gf to do the faux marble or Google faux granite. You'll end up with something infinitely better suited to a cab, far less costly, and easier to machine and/or fix if the need arises.
You've also got to take into account that you're adding weight to the front of your cab unnecessarily. You may have to fortify the CP just to even use granite, but from the looks of the size you'll need, perhaps not.
Basically I'm saying granite, while it WOULD be super sweet and cool and durable, just isn't very practical for this application. If you could get your hands on a slab of Corian or something similar, THAT might be a winner-winner-chicken-dinner idea, plus you'd be able to machine it yourself.