Hi...
For me, a 4x4 van is ideal for adventure travel—it's THE vehicle that gets you off the grid to remote sites, a bit off the beaten path.
So I'm looking for the same thing as you, and there are definitely topics we could discuss. But I'm mainly writing this to encourage anyone searching for their vehicle, because with a bit of time and maybe a bit of luck I managed to track down a B110 4x4 decommissioned from the CRS, which I hope to acquire soon and convert into a camper van.
A few search tips: In France, most vehicles of this type (B110/90, Iveco Dailly, Trafic, C17...) come from public sector sources like police, military, fire services, and EDF. You find them first at auctions, then with mechanics, sometimes specialists, who buy vehicles for next to nothing but without any information from the agencies (presumably maintenance and upkeep are high quality in the public sector anyway). The professional then ensures compliance (technical inspection) and in principle a complete overhaul and/or restoration. If you have the means and motivation to do everything yourself you can try auctions, but in the end I'm not sure the advantage is that significant. Especially since you'll have to deal with professionals who generally organize among themselves to make sure they secure the vehicles (watch out for bidding wars).
Otherwise, even rarer—Mercedes also produced vans or converted buses as 4x4s for Swiss, German, and Dutch armies, I think, in very limited series. At least in Europe, because in Africa and Asia these vehicles are very common. They're more robust than those from French brands, and in fact you find way more spare parts on those two continents. The rare models (in the 300–600 series) still available in Europe often end up going to Africa.
I don't know how many vehicles of this type from public sector sources are still in service in France, or in which regions, but I'd guess if there are any left it's mainly in mountainous areas. Auction sales happen primarily in the regions of origin, but not exclusively.
As for the B110 4x4, it's definitely quite rare—personally I've only seen two in my whole life, so I'm really hoping to land this one. I started with a Trafic semi 4x4 (reinforced chassis and rear axle locker, but no differential...) which took me to West Africa, which I'm now letting go of (interested buyers welcome) to soon acquire the rig I found—the one I needed for the next few years (2 projects, in Africa and Asia)—while I wait, maybe, for a bigger one down the road...
There you go, happy searching...
dd