That's a nice looking sprayer, Glamisdude. How is the pressure? Is it good enough to spray mud off of boots, for example?
I, too, built a Motorpig-type setup and fell victim to small leaks. Through trial and error, I have spent well in excess of $150 on it, and I'm still not super happy with it. My most current version actually does work very well and has a lot of pressure. However, I am still experiencing some small leaks that only pop up when it's pressurized, so I leave it full of water and un-pressurized until ready to use. The one I made runs the lenght of my roof rack between my home-made cross bars, which is just short of 40" total. Unfortunately, this equates to just about 1.3 gallons of water.
Now, with my new roof rack on the way, I'm faced with a dilema: do I go spend about another $60 or so at Lowe's on more pipe and fittings that will work with the new rack, and build a new one using the knowledge I've gained from my first few attempts? Or do I just buy a commercial solution that would work?
Not sure if anyone has seen this, but I stumbled upon it at the Bass Pro store a few weeks ago. It's called the Rinse Kit, and is a relatively new product. It only has two reviews on Amazon, but they're both 5 stars. It gets it's pressure from being filled by a pressurized water source. This means there is no pumping or batteries, but it also means you can't refill it in the field with a jerry can. According to their website, the company will be offering a "field fill kit" soon, which will allow the unit to be filled with water bottles and pressurized with an air source such as a bike pump. At only $89 and holding a full two gallons, it's a much nicer option than the Road Shower in my opinion (which is $300).
Check it out:
http://www.rinsekit.com/