So it's a mouse on ball bearings. This isn't a new idea:
I had a mouse with ball bearings once: the R2 Omnimouse. Those certainly weren't "zero friction", and I highly doubt these will be either, especially when dirt and deformation of the mouse under hand pressure are taken into account.
And even if it is "zero friction", is that even a good thing? What about control?
And even if it
is a good thing, is it good enough to offset the increase in mouse weight?
Also, just thought I'd mention, according to an ESReality thread, the guy who did this conversion wants $450 for a kit. Not a chance.