Is there a way to make a clip pan from left to right during playback in real time? I have sort of accomplished that by copying the clip and panning one hard left and the other hard right, then fading the first clip out and the second clip in. It would be nice to do this with just one clip, though.
In a word, no. You’ve found the best work-around.
You’re talking about pan automation, similar to the “Clip gain” tool. AFAIK pan automation is not in the roadmap.
An old Audacity plugin …
I don’t know if it works on Audacity4 though.