well, I did it... got some clear contact paper, and I already had a 2x4 sheet of Masonite laying around for another project (fixing an old Dual 1019 turntable base)
just cut about 16" off the end, because my the desk I'm using the keyboard tray is a hair under 25" wide, wrapped that with the contact paper (actually some off brand) and cut a piece of shelf liner to go between the Masonite and the desk. Looks OK, feels great BUT tracking is awful... it works, but not well. Back to the drawing board, or more correctly, using sheets of printer paper for my mouse pad... maybe I should go to a real store and get some "real" contact paper maybe in black this time... OR... I wonder if vinyl would work? I have some sheet vinyl laying around from recovering the sound bar on my Jeep..? don't think it would glide nicely though.
Edit: I think it is just that this mouse sucks. I'm starting to see why I thought it'd died on me a while back... After using it on my new "mouse pad" for a while, it just stopped moving the cursor altogether, I guess it just gave up trying to track. So maybe due to wear or something my mouse pad at work became untrackable to it, but it worked OK at home... Unfortunately I've yet to find anything that it'll track well on, save for a sheet of paper. A little disappointing for such a comfortable, well shaped mouse.