Pretty much built the same thing but on a somewhat smaller scale. Was looking to replace 35 gal tank on ATV so built this 65 gallon one on a carry all frame electric pump about a 15 ft boom less nozzle as well as small boom section as wide as platform and a hand gun on a hose reel all ran by a 12 volt pump and selector valve.

Goes on a 8N for mostly spraying yards lanes side ditches, gravel areas around buildings etc. have even done a little field small area spraying as well. Pretty good load for 8N weight wise makes it pretty light in the front so for more gallons probably need something bigger especially on slopes.

http://talk.newagtalk.com/forums/thread-view.asp?tid=464550