I'm not sure how you would maintain even tension on all the layers when you unhoop and rehoop. I would think you would still need to pin the sandwich. I have seen this done on old episodes of Georgia Bonesteel's lap quilting show, but she always used a QAYG method and worked on small squares, not a whole top.
I really like using gloves to hold and manoever the sandwich. You can get 'real' quilting gloves, or use gardening gloves. They both have a rubberized coating on them which gives you grip on the sandwich without having to grab it with your hands.