I saw the guy from Noslip hoops at the Cinti quilt show last month - and his product looks wonderful - well made. He also makes his own stencils, and focuses on the hand quilter!
My suggestion is baste, baste, baste. Look for Susan Schamber's method of basting. I do that now, and my quilt never shifts. I feel (esp for the larger quilts) take the time to baste the quilt (and it may take a few hours to do it well) but it was well worth the time because NOTHING shifted as I quilted on it.
http://www.youtube.com/watch?v=bhwNylePFAA