Summary

The new 5kg rolls are available

http://www.zyltech.com/5kg-texas-size-spool-ceramic-white-zyltech-pla-3d-printer-filament-1-75-mm-11-lbs/

I got one and wanted a center for it. Designed it in Fusion 360. Hang mine above the printer, below a shelf. Use a 1/4" steel shaft in the center.

This printed with 3 layers thick and 20% infill. I wanted it to be sturdy enough to support the weight of the roll.