About five minutes passed between me thinking, “I’m gonna take a break from picking up new music gadgets for a while” and someone online offering up hand-modded, circuit-bent cassette recorders that can change speed with CV input. This just arrived. (Not DIY. SEDIT: someone else did it themselves.)
And new inputs (one for CV, the other to add audio-in, versus the preexisting microphone) require new labels: