I'll be interested to see replies to this... we just bought a house, and will be looking to do the same in the near future.
I've seen a place on Hwy 55 between the Apex area and Morrisville, headed towards Durham it's on the right before RTP. It's called The Stone Center of Carolina. just google it, it comes up the stone center dot com.
Best of luck w/ your project! Post pics when its all done!