Here's how far I was able to get with it, I'm sharing in hope that somebody can improve it:

 

Just an idea: Would a belt tension arm (with a soft shock absorber) work here? It would keep the belt centered and also correct certain slipping. Normally it's not needed as the belt length should stay the same regardless of the ratio, but for this construction it's maybe helpful.

Cool 

 I’ve always wanted to see a cvt from LEGO, which you’ve done twice.....

Well
If you manage to finish the "Variomatic" (invented in the 50's here in the Netherlands) than you (or Lego) can add a famous car to the collection.

The "Truttenschudder" (met jarretel aandrijving)
Better know as the DAF from Van Doornes Automobile Fabriek.

Oh well.
It would be great to see this car next to the Beetle and Mini.

The guy she tells you not to worry about...!!   

Fascinating!

CVTs are one of the "frontiers" of Technic, I suppose, and that is a very unique solution. I am still waiting for a heavy-duty manually-controlled one, though. Good work!

Excellent proof of concept, as you captured precisely how pulley-based CVT's work. The weakness (as you've noted) is the pulley, as it bends easily ... I wonder what other options are out there. For example, two tapered discs, and a rubber wheel in between them.

Very interesting!  I've never even seen that dish part before.

What if it could be made smaller somehow? Very cool though.