Added one to mine
Got the track through BoatUS. It was in their catalogue a couple of years ago. It's great, very flexible, come with hooks, etc (about $15 as I reacall.) A few small screws into the header (very short ones) and your done. I mounted mine in a big "U", which extends outside (over top of) the head door out over the full drain pan. That way the shower is usable, you're not sitting on the head to take a shower, and all the water still goes into the pan. You do need a wider shower curtain than most. I found one that was designed for a freestanding tub. It's a silky cloth like material and is washable. Good luck. You might also try camping world, the BoatUS type place for RV'ers.
