I have my SX3 on a very nice Newport steel table with like 4" square steel tube legs. That being said, the coolant base I made is comprised of like 4 layers of 3/8" or 1/2" plywood glued up and mounted to the surrounding base that is fiberglassed. I think you will do fine with a sturdy wood bench, and I have mounted aluminum discs about 4" in diameter for the leveling feet to sit on. Being level should not be a big problem as the machine has 4 leveling feet that can be used to correct that. Just make sure the constuction will support the weight of the machine well without any sag or wobble. Diagonal support rails implemented on each side should make a wooden table very stable.
This way you can spend the cash saved for tools and accessories?? Good luck and I hope this helps. It would be great to see some pictures when you get it done.