Why not just replace it with a new shower head assembly, sold at any Lowe's or Home Depot, and even WallMart? Get one that has the attached hose and shower head, or just get one with a new hose. If it comes with a hose, it will have the holder for it too. Simple to replace. You may never find an exact match unless you purchase the entire thing, as you've said, and you'll probably pay much more through your dealership than a big box store. Besides, it's a great opportunity to get a beefier shower head; maybe one with different sprayer functions by rotating the dial on the front.
$12.96 for this one, similar to what is stock in most campers. Click here.