Head mass, bearing slop, rod flex, apparent bed warp

All these are mentioned in a variety of posts. I think I’ve read most of them, but I am a rookie at all this, so I have this question please.

“Warped bed” (high in the center)issues seem really to be caused by rod flex due to head weight. I think the general conclusion is that the Taz would benefit from stiffer rods and linear ball bearings.
Has anyone designed parts/created files to upgrade to 12mm dia rods and bearings? Or for another solution?

This post, from wantmys2000, lists the parts that need to be changed:
“The 10mm bearings have the exact same dimensions as the stock IGUS bearings. That means it’s a simple part swap. If you went to 12mm you would need to redesign new bearing holders for X and Y carriage, print new Z guides, print new Y end brackets, and drill out all the aluminum plates. Lots more work, much greater chance of messing the machine up.