I just tried a handi-quilter at the quilt show that was mounted in a sit down table just as you described. I also tried out a Flynn frame and now am the proud owner of one. I found it worked well for me. You are supposed to be able to purchase relatively cheaply, conduit at the hardware store to extend the frame to use for up to a queen quilt. I can hardly wait to get it set up and try it here at home.
I do like your idea however, how clever.