I've started to work on it 2 years ago, and there's still much tweaking to do, but to give you an idea on what we've done and where we're at...
I got a Martin portable on-demand hot water heater. Part of me wishes I would of went with the L5 for the sole fact of being able to get a pelican can to store it outside of the trailer. My initial plans and why I went with the Martin may of changed. Regardless, it heats and works super well!
I had a change room and decide to convert it to a shower (see it on the right of the truck). It worked on, but those change rooms are not fast to setup, and kind of cheap.
Last year, I decided to jump in and get a full awning with sides, and one of the ideas we had with the large amount of room that we have with it, was to split part of it until a shower and change room.
That does work quite well and not bad to setup with the tarps we have. We got some heavy-duty tarps we bought last year for use at a haunted house this year that we're planning on cutting and shaping to make a proper change room/shower divider. The only issue to really deal with was the floor/drain setup. I wasn't a fan of using the rolled tarp setup, having to really plan and use the angle of the terrain. There is a drain capture floor you can get, and they do advertise it for use with changeroom of Xterrachris81's style. It's called the "Paha Que Tepee Drain Capture Floor". It was on my list for mods this year, but with this thread, I decided to relook, and I found one on Amazon that was used-like-new (1 left) for $30CAD shipped and ordered it on the spot! The nice thing is that I can connect a regular hose to it to drain the water away from the camp !
http://www.hotcampshowers.com/inc/sdetail/371