Hi Marc, Frido Welker, Enrico Cappellini and their Copenhagen and MPI colleagues are hoping to do some of what you outline with enamel proteins (e.g. Denisovan jaw from Tibetan Plateau). Main issue will be preservation, as always.
My group is hoping to maximize our possibilities by working with mid-Pliocene fossil mammals from Ellesmere I. in Canadian Arctic Archipelago. Collagen preservation is outstanding, should be similar for enamel proteins.