The one I mentioned in this thread (Remember Me This Way) is the only one I can think of that I would consider trying to finish if asked.  Or at least pre-SAMS, I would have considered.  Nowadays probably not, but it would be in my wheelhouse.  I think finishing someone else's story yourself kinda takes the fun out of it, though.  I would rather enjoy it as a reader.
I hope you do get back to your story and writing in general, Steph!  We miss you around here!  If it gives you any hope, Rose, Dee, and I decided to resurrect 00Carter about a month ago and just finished our first episode in 9 years this week!  We're not ready to post anything yet, but will have updates at some point this fall.  So it can happen!