i have built a few of these, and they all seem to work ok, as long as the water temps stay down.
i have built a 5g version, a 20g version and a 27g version.
all were built using a small/cheap aquarium pump, 1/2 pvc and 360* misters. i ran the cloner for 1 min on, 4 mins off,
with one of these timers
i used a bit of nutrient in the totes to get the clones going as i didnt have much luck with (my) water alone. i also noticed that if i just let the water run i wouldnt get as many roots. i was told it had to do with the water temps, and the problem went away once i added the timer.
like Derick mentioned, most of the parts (misters and neoprene holders) can be found at local hydro shops.
hope this helps.
http://www.cloud9farms.com/ - Southern Colorado - Zone 5 (-19*f) - 5300ft elevation - 12in rainfall plus irrigation rights
Dairy cows, "hair" sheep, Kune Kune pigs, chickens, guineas and turkeys