I use this stuff on my table saw and router table for jigs and the like. Mine came from Rockler because it was cheaper but it's the same manufacturer.
Here's the deal; it has a contact adhesive backing that moves a lot under the indirect pressure of use during woodworking mounted with a wood or Al. backing material. While fine for the purpose - that of improving slide between two surfaces with little load - I don't think it will take any significant direct pressure. I've removed it from all but a few jigs. The material itself is relatively soft. Reasonable use noticably scores the materials face - again remember that's with no direct pressure or load. I've also had movement when used in a fence saddle jig where either the glue, the material or a combination of the two were sufficiently soft to allow enough movement to misalign and bind the jig. Tightening the jig fit made the slide too hard to move with the material so it got tossed out - now just use hardwood on Al. with a bit of wax.
So, interesting idea, maybe it would be ok for a wrapped style bearing on a ground rod or what ever so maybe its worth an experiment, but it would still not be sufficiently stiff for a small cnc I think.
In contrast the Delrin often used in these pages is significantly more strong and resiliant than UHMW and the Igus material is many many times more so that Delrin.
Chuck, I noticed your machine from way back and your ideas on hexapod style machines, how are they running? Maybe you could cnc up some carriers to try this uhmv tape and let us know how it goes.