Thanks for the pointers.
Having a UV lock control to that nature would be useful for flowing object structures with more complexity that could not be created by extrusion alone. But, no doubt a future FFD type distortion command would allow for that as well.

I didn't notice before, but your first example appears to be similar in effect to Corel's good old trusty Envelope (distortion) command.
I'll find that useful in the future.