Been doing research into commercial level CNC routers and the possibilities of something with ATC. Came across this video, and this seems like a machine a lot like what I was envisioning for a more 'purpose built' T-O-M machine that would stand alone; just at a much more industrial scale and setup more as a turning center. I'm thinking that giving this overall design the "hobby grade" treatment using more extrusion and such, and maybe omitting the ATC for a standard low-cost spindle, and then printing up Fritz' T-O-M headstock and bearing array, one could stretch this whole thing to any desired length. Also if one was dealing with strictly tubing which is consistent diameter, you might be able to get away without needing full surround bearings between the headstock and tailstock and just having little adjustable roller rests that support underneath the tubing during drilling ops. This prevents you needing to remember where your supports are.