Ok, my curiosity was running wild and I had some old skate wheels from the 80’s, and a garage full of woodworking tools. Here’s the result.
It works fine. The travel when I ride them is minimal - maybe 1/4” back and forth. Probably around an inch when I stand. But it feels like enough to make a difference. I don’t feel it in my quads as much when I stand, and first impression is there is less “roller fatigue”. A pretty simple project. Btw I noticed while I was riding that none of the four center wheels were in contact with the rails, so I removed them.