I'm surprised nobody's put this up
http://www.wetruck.de/
Could give you some ideas.
It was up for sale by tender last month;
here
I would have loved to know how much it went for.
(or maybe not, if it turns out that it was within my reach I'd kick myself for a long time after)
I dreamt a hell of a lot about an amphibious off-road motorhome, eventually concluding that the simplest (ahahaha!) would be to cut the armour off an OT64 SKOT and build a body onto the resulting hull/chassis.
But realistically, I kind of came to terms with just HOW much work is involved, and wanted a camper quicker. (insane laugh, I'm doing a hard side pop top 5.5 m long! quickly? I don't think so!)
Maybe for the next one...
I wonder where they put the fuel tanks on the Bison; it's based on a KAT, so the tanks have to be pretty large.
Hope the Bison inspires you a little,
and I'm sure you know of the great A to Z of amphis
here
Go for it! The amphi landies aren't load carriers so the tubes don't need to be moved about; be careful to ensure sufficient flotation for the truck when it's laden, maybe do the camper build before the floater build, that way you won't get a nasty surprise.
Much luck, and will be following with interest.
Luke