i just tried to track my MX700 on a clear acrylic glass that i cut out
its about 4mm thick

so its kinda thick and the result was no good
it didnt track well at all

up next in my test is a cd protector commonly seen in 50 spindles of CDs

the test subject had a grainy side to it
it was much easier to slide and glide the mouse on the grainy side

the thickness is pretty thin
only about 1.1mm

so how did it track?

very well wherever the transparent plastic protector is placed
and while grainy, you can still see the pictures under

but i dont think this grainy effect can be achieved by sanding a smooth plastic surface
sort of like mousepads, it has to be mouses, or sprayed on

im sure there are such sprayons you can find
just hard to find