Underfloor Storage

A mate and I are in the process of designing his offroad TD and are trying to figure how we can have about 9" underfloor storage and not compromise the bench height in the galley area. It needs to be about 7' long by about 14" wide to store his Oztent. He also wants to have a water tank under there. I've browsed through the design library and can't seem to find anything suitable. Any ideas?
Cheers
Paul
Cheers
Paul
