Idea: Rotary for tube cutting at gantry home position?

I once cobbled together a 4th axis stepper motor rotary along with a pair of other linear axes to make a CNC MIG torch welding system for welding around the perimeter of a pipe. I was thinking that if the XR gantry homed to a location positioned over a rotary, the gantry axis could be used to cut pipe on the rotary.

Has anyone seen this on a plasma table? I have seen it on a CNC router for milling aluminum tube fish mouths. I may have to make one. MACH3 makes it pretty easy to do along with a Gecko Drive G540 4 axis stepper motor controller board. Given tube diameter, I think it might be easy to drawfish mouths in Solidworks and un-roll them to create a DXF file to drive the Y-axis. The rotary motion just needs a Pi ratio factored in to its motion which I think MACH3 allows somehow.

update: I found this:

This is the CNC aluminum tube cutter I had seen before using a gantry router: