Hi Simon
Getting a custom body built for a Unimog could cost anything between 10,000 and 25,000 pounds depending on the spec - prices quickly add up with solar panels, heaters , windows , ovens etc.
I have some pictures of my 1300L and an info sheet I can send you - contact me on <unimog4sale@yahoo.co.uk>
FYI my Mog is for sale Euro 32,000, 1986, OM352A 168hp, Right hand drive, sleeps two, shower, toilet, kitchen, solar panels, generator, moped - too much to mention here. Have a look at:
Unimog Camper, 1986 1300L, Located Tanzania - The HUBB
Regards
Gavin