I've never used this as a camp shower, but it could easily be adapted. I do a lot of dry-camping where I fill 6-gal water cans at the ranger station and hall them to the camper in the back of the truck. The tank in the camper holds 26-gals which is just over four jerry cans. 6-gals of water weighs about 50 lbs and I was getting quite a workout lifting and holding these up, to pour the water into the camper tank.
I took a ShureFlow, 12v water pump I had from an old camper and mounted it in a plastic toolbox from Harbor Freight. I installed a 12v jack in the back of the camper next to the water input (a-la cigaret lighter), and wired the plug and leads to the pump. I threaded hose fittings onto the pump's in and out ports and I keep a couple lengths of clean water hose in plastic bags.
When I'm ready to fill the camper, out comes the "pump-in-a-box". One hose goes into the jerry can, the other into the camper's water fill, I plug in the power then sit back and enjoy while the water transfers. At full flow, it take about 3 minutes per can.
One could easily tee the output from the pump; one being cold water direct to the shower head, the other being hot water (perhaps running through a coil of copper tubing in the camp fire, hot box, or solar collector), then to a valve to mix with the cold at the shower head. Tons of possibilities here.
I apologize that I don't have a picture to share. My box is in the camper which is still in winter storage. Just imagine opening a toolbox and having a water pump inside. Simple enough.
