I found a lot of spool holders but for the specific design I was looking for they all required real bearings.

Since I had some teflon tube lying around, I designed a wheel that has a teflon tube bearing.

I provided screwholes in the base to fix it if you want it to be fixed.

The 2 color base on the picture is due to the fact that I used some left over filaments fused together.

Assembly:

1. Put in the slider in the base
2. Assemble the wheels
3. Cut 2 teflon tubes of 97mm.
4. With the slider on the same side as the base wheels, assemble the teflon tube and bend-squeeze it into the other side so you have a teflon "rod". Adjust the slider to the required size and start printing :-).