Wonder what would happen if you got a heavy piece of lumber same size as your desk top, only longer/deeper and then glue and nail that piece over everything. ?? I suppose you would have to put legs on the extended part, however. I doubt that it would be good for bearing down upon to rotary cut things. Do not think it a good idea to try and cut hole for machine. What would hold the machine at that location? Wish DH were home right now I would ask his suggestion. Years ago I sewed upon a church-like luncheon table and it had plenty of room to each side. Then I would put ironing board to the back side at same level when I needed extra width. Just a thought.....good luck.