. . . and Shimano Airlines.

Largest problem I would see, cheeto, is to make the reverse-valving seamless. There would have to be ratcheting, positive pressure both ways (no return springs); so the reversing valve would have to actuate instantly when an upshift or downshift lever was engaged. On second thought, I suppose it could be a single-acting system with return springs; but where would that get you other than you eliminated a very simple, efficient cable?

I vote for CVT.