I don't know if a script for this exists or not, but i just did it just for fun.

create a path, name it "from"
duplicate the path, name it "to" and deform it however you like as long as the path has the same number of points (control points) as the first path("from" path).
Then run this python-fu plug-in (available under Image/Python-Fu/Create Paths between from and to...)

It'll do linear interpolation of the control points and create number of paths between these 2 "from" and "to" paths.

example
start with something like this

and end up with something like this, at which point you can use these paths to draw stuff and animate them or anything.

well look at that..it already exists.

Just downloaded trandoductin and thank you for showing how to use the script. Thank you Wallace for advising about, Ofnuts plugin. I have plugins that I really don't know how to use so will play with both.