Already have a small lego table but son is outgrowing it. Would love to do this on a bigger size table for him. Would be good for a kid's playroom. If you did velcro to attach it, you could switch out the base plates maybe.
@ Lauren- something for boys-Portable LEGO Tray - Brilliant! You could even hang these on the wall of the toy room. Also, great for a portable play surface for the kids when away from home, just make to fit inside a book-bag or back-pack :-)