I'm sure there is a thing for cars that replicates different engine noises ( in the cab). It might be a good idea for Electric bikes - "what shall I ride today? ....Big Harley V twin, CBX -6, Classic single, or maybe 2 stroke triple?"...
Yes I was thinking on similar lines Steve. My mate, has a mate who reckons he could do that sort of thing quite easily. There again he does write alga rhythms for a living. Clever beggar.
He even says it wouldn’t be that hard to have it so that the more you twist the throttle the louder the sound, just like a “real” bike. 🤷

Cheers, Michael