My cutting table is a 3' wide solid core door, set on top of two bookcases. It used to provide lots of room for cutting, but now the AccuQuilt Studio is at one end, the cutting mat (24x36) is at the other (currently covered with fabric being selected for a quilt), and the middle is full of rulers, rotary cutters, container for throwaway scraps, and assorted things that belong somewhere else. My theory is that however large the surface, I will fill it.
I have discovered that I can use my longarm table for cutting batting and trimming quilts after they're quilted, so I've pretty much covered it with cutting mats. It's not the perfect height, but it is 12' long.