In the Good Old Days (Feb. 1991!) I wrote an article for Audio Amateur on a remote control volume and balance control I designed. The design was based on a set of potmeters driven by stepper motors. The actual control commands were provided by a standard IR remote control and the receiving circuit commanded the stepper motors to rotate as required, setting each potmeter to a setting for the commanded volume and balance setting.
I finally got around to scanning the article. Enjoy!