If you find a hopping foot for a top clamp, please share. I plan on making one later this summer, so we'll see how that goes. I've got enough feet to mess with, but will probably go with a bar mount setup using older bar clamp feet. Not sure if you machine as a screw on adaptor or a slip on adaptor with a set screw.
I also wonder if you couldn't replace the presser bar with one out of Singer machine - but I'm not sure if Singer feet would fit - as you'd have to have the needle hole in the right spot, and I think your machine is slightly off center - but for a hopping foot, that might not matter - just get one with a bigger circle- and know that the needle is not centered. Should not be a problem unless you are doing ruler work, and I don't think you would with FMQ.
I plan on spending time figuring that all out so I can use some of my older top clamp machines for FMQ - I do have a darning hoping foot for my Standard machine, and it will work but the foot is very small in diameter compared to modern hopping feet.