Behold the mighty Citadel_Paint_Holder_Version_2_12x_Stackable_Rotating_Über_Rack. Works without the foot part with just connectors but i bet you want to print them anyway to get that sweet sweet rotatory action. Superglue parts connector part 1 and connector part 2 or 24 ml files together, if you're going for additional layers which you obviously will since nobody who has a 3d printer and paints minis has only 12 bottles of paint. If so, buy more paint you stingy Scrooge McMuffin.
Made more to fit 12ml bottles but if you need to put shades on lower layers use 24ml connector in between racks.
Print time for holder 12x ~7-8h + ~something for other doohickeys.
Revision 1: New connectors and got rid of the bearing, if you have already printed a foot piece I added a bearing correction piece you can glue to the foot piece instead of printing it again. Added a "hat" which fits 7 Vallejo/Warpaints + brushes, tools and trypophobia.
I encourage printing the revised connector parts for sturdiness and funktionality, If you have printed anything so far.