FreeCAD parametric spool holder rollers for a 3D printer. The sizes in the files match a 10 cm long extended roller for the FABtotum, but you can edit the FreeCAD file to make it your wanted size.
With 10 cm you will not be able to fit the side panel of the FABtotum, but you will be able to use most big spools out of the box without needing to un-spool and re-spool to a smaller spool size.
Mines were done with 8 mm inner diameter, with matches the ones comming with the FABtotum, but was very difficult to put the bearings (the ones coming with the FABtotum) in place, as they were too tight. I have modified the file to 8.1 mm, so that you have less amount of trouble. You still might want to tweak the file to a larger value.