Juin Tech M1 or
Motoko MTB are cable actuated hydraulic brakes for MTB. Not exactly cheap, but more or less do what you asked for: the two pads can extend by a different amount.
Make sense for road levers (I think it was
katsup whose post prompted me to upgrade to Juin Tech R1), for MTB you can probably just go full hydraulic.
Since we are mentioning Klampers, it probably makes sense to mention Juin Tech M1 as well
