Yes, very dusty, but stable. I built the bottom of my stairs with mdf that I was able to mitre, sand, put drywall mud and paint it and it looks like a monolithic piece now.
I've played with the idea myself. I was actuall thinking (at one point) of making one that hangs on the wall, but folds down onto a table and does the cut horizontally (flat).
A CNC would be cool, but would hate to wear out a spinning bit for a 96" straight cut, but I don't know enough about the hardware to know if that would be extreme or not.
If the space grows and there's room and budget, I think having some plywood available for people to purchase would cool for projects, but that's wayyyy down the line.