If you extend the way bars 3-4" (75-100mm) past the end mounting you have room to mount? a cnc stepper motor while maintaining the center distance.? I think someone was planning on making 2 piece pens make a mount for the mandrel that screws on directly to the spindle You may have to part a bit off of a few bushings so that you can buy a little space, Live center not sure if using the 2bearing live center is worth the difference in distance between centers.? All of this should buy? you the room to turn even El Grande and Cigar pens
Ed Samsen