MapTester Awesome setup...! Awesome use of wasted rack space too! That box has great visibility and probably waterproof...#1 on my mind now that the moonsoons are here!
Rainman...Do you mean like this? If you show your marine guy a picture maybe he can get something cheaper...or maybe you can make an O-ring from old bicycle tubing to block water.
http://www.go2marine.com/frameset.js...egoryId/13115/