Looking good, Dennis.
I could see building something along the same lines to attach to the bed of my lathe (Powermatic 3520B) to use as a small workbench and clamp. I've got a 1 1/2" thick piece of melamine-covered particleboard that I set on the bed occasionally to use as a small benchtop, mostly as a flat place to set tools and finishes on. It doesn't even attach to the lathe and I still find it handy. I can see how having something more substantial with a vise (and that can be clamped to the lathe) would be useful.