Can't say where I came across this "VelEau installation," but I thought it was worth sharing. The hydration system is being tested by a few riders in training and you may catch a few of them in action at the upcoming BC Bike race. I'd look in Sue's direction...
The seat pack supposedly can hold up to 40 oz. The mouthpiece is on a retractable cord that will pull it back into place when finished drinking. The rest is up to you to try and decipher...

I recently had the opportunity to demo one of these VelEau systems at Mountain Bike Oregon in Oakridge, OR. I must say I was skeptical at first because my CamelBak was serving me well, but I never liked having that hot, sweaty pack on my person. The VelEau is well engineered with a cool tube routing and management system, bomber rachet strap (like those on Side shoes), room for tools, easy to clean, etc. I thought it would be in the way on steep technical descents but it really wasn't..I just straddle it as if it was an extension of my seat. The VelEau guys call it the 'back seat'. I keep seeing more and more of these at mtb races and on touring bikes so it must be catching on. I'm seriously considering adding one to my quiver, esp for those 2-3 hour rides, races, or touring.