The only "sew control" I could find for a longarm was the stitch regulator for a Bailey's Home Quilter. And the photo says Deagle Sew Control AC-100 on it.
I believe what you're actually looking at as far as the longarm brand goes is a Bailey's, which I seem to recall is an aftermarket-stretched Janome.
Bailey's Sew Control Regulator
Depending on the age, it looks like Bailey's kits their current Home Quilter with a Grace Continuum frame
Bailey's frame-mounted long arm
These are the only pages I found also. Thanks.