The problem I see with the string potentiometer is the return spring. You have to work against it and I think it will limit return speed.
Yes, that's what I think... I've never used string potentiometers so I have no idea what kind of force is involved, but it's likely enough to upset playability.
How about a length of resistance wire mounted on the body and a wiper attached to the slide? Same effect but no spring to work against.
This is an intriguing idea. I think I could make this work, but I really don't know where to start (I'm more of a software guy). Could you point me in the general direction (products and projects I should look at).
I'd been looking at this problem myself. I see that very thin nichrome wire is ~40ohms/foot and videotape is about 100Kohms/inch. Any suggestions for something in-between?
Are you working on a trombone slide?