Someone on the QB moved their midarm machine from a frame to a sit-down setup and is much happier with it that way. Sorry, I don't have a link to her thread with photos, but I know it exists out there somewhere!
Do what is best for you. It sounds like moving the machine to a sit-down area and selling the frame is what suits you now, so do it. You can always set up a new frame later, if you want to. At that time I would highly recommend going with a midarm and longarm machine, though, and buying both machine and frame together.