I've started one. Personally, I could not cut up the jeans using scissors or rotary cutter -- way too hard on my hands! I pulled out an electric scissors I bought many years ago, and that worked very well to cut up the jeans. It is fast and easy on my hands. However, I still had to rotary cut the denim into shapes. My advice is to get a pair of electric scissors for taking the jeans apart, then take your time cutting the shapes out of denim so you don't stress your hands too much. Almost all of my jeans are stretch denim and I think they will work fine in a quilt. However, I don't think stretch denim will fray the way non-stretch frays. You might want to take that into account when you choose a pattern. Or you may want to send some pieces through with your laundry multiple times to see if the edges fray or not.
There are some wonderful ideas on the net if you Google "denim quilts" and then hit images.