RoyB ... great design and thanks for the link. Sounds like Phemens did something very similar. However I am not sure this mod will work for me. As far as space goes I could move my tanks forward and install one of these tool boxes (I actually have a spare) but I will run into problems with the fold down bunk. It is an 08 so is still pole based for support. The spot the pols go into on the frame are directly on the top side of the frame next to the existing battery spot. I have a bad feeling moving my tanks will get in the way. I am still going to go home later and take a look and see if there is anything I can do.
thanks again for the advice. :)