Here's a few pics of what I have been messing around with off and on. I made a sling out of some seatbelt material I ran across- it's not screen accurate, but it's close and this is a Matrix/Snow Wolf so it's not going to be SA to begin with. Needs a stouter "D" ring on the back. The hardware is from a laptop bag strap, cleaned and the silver color darkened with gun blueing compound. Stitching is ok, but I was rushing.
The PPS M870 looks like it will fit OK, but until I get the shroud figured out I'm not going to make any progress.
Mark