Revolving tailstock chuck - video

Revolving tailstock chuck. By Cutting Edge Engineering Australia. 13:38 video:

https://www.youtube.com/watch?v=-E1NkckJdbs

Elegant!!!!

Tailstock chucks are common in shops doing long shafting or rollers...but I've never seen one include spigot of the back plate.
I'd consider best design uses double taper or angular thrust bearings to keep load close to nose of Morse taper as possible. They've all bored right into chuck body, or retained bearings with a flat back-plate. Many were mounted on #5 MT's to support 1000+ pound shafts.

Typical use is repair work; dial both ends in each 4-jaw, turn a shallow band for steady rest, back tailstock off, then bore/ turn outboard end for bushing or sleeve. There is no other way to achieve concentricity 10' away from headstock, when most lathes have 2", maybe 4" of spindle bore.