@Shauki made any attempts at printing the wheels/sleeves?
I tried it quickly the other day but to get a smooth motion the surface/v-groove of the sleeves definately need post processing. Putting them in a drill and using a file for a lathe-like operation made alot of difference but in order to get good repeatable results I think a custom jig or pulley lathe would be better than free hand smoothing to get the diameter of the contact surface the same for all wheels.
The hardware in the images are M3, and bearings are 3x10x4mm 623ZZ. The design is inspired by Makerslide-/OpenBuilds V-wheels.
(The sleeves in the photo are extra rough since I upped the resolution in OpenSCAD and it didn’t work well with my current slicer settings. The previous attempt was much smoother.)