It's supposedly a French military truck made by Simca. Officially, the Simca Unic Marmon Bocquet (hence the acronym). Anyway, before sluffing it off as French, it's supposedly got a Ford V8, and "Unimog type suspension and chassis" according to rrservices.co.uk.
It's got portal axles and maybe even a Renault 3.8L, 4cyl diesel from the TRM-2000 series according to http://www.milweb.net/features/sumb.php. (I don't know about servicing it on this side of the pond though...)
Anyway, with a starting price cited at £1500, I was wondering if they might be worth looking at.