Inspired by Michael521's great hidden-electronics conversion kit idea (thing 18044), I set out to to the same thing on the slightly oversized Mendelmax variant that I am building. These y-rod holders are made for 8mm y rods. They include a hole for small screw and a slot for a trapped nut that together, act as a clamp although in practice, clamping doesn't seem necessary. The outside facing part of the holder has a channel allowing the use of a screw and washer to tighten it to a trapped nut in the T-slot.

The main reason that I went this way was because I hope to mount my bed directly to igus pillow bushings, reducing bed weight & height and hopefully resulting in no need for bed-leveling. Another benefit is that now the rods clear the hidden PSU. If I need a little leveling, I figure that these individually adjustable holders will do the trick.

A quick note: This is still an experiment but I think it should work.