You can run into problem where the brace supports inside need to be modified so the machine will lower all the way. These are blocks glued to the inside of the cabinet that the machine rests on when lowered. Since the machines have different outlines, sometimes they hit in the wrong spot. I've had a few identical cabinets, and the location of those blocks was the only difference.
As to having a treadle that will go in reverse - you only need to find a machine that is treadle-able that has those features. I've got a 401G and a Necchi Supernova that can both be put in treadle cabinets - and they are machines with lots of neat stitches and functions.
Check out what ThayerRags has - he'll treadle just about anything!