Hmm, I'm not quite sure why you would want an auto thread cutter feature on a quilting machine. Especially if you want to knot and bury threads down the road. If I am not knotting and burying but taking very very tiny stitches close together to lock them in place, I always test to make sure my stitches are locked before cutting and I guess I must be missing how you would do that with an auto thread cutter. But I have a stand up Innova, not a sit down.
As far as I know none of them have auto threaders. You may want to look at the Bernina