The prices of just a decent conversion camper van is pretty crazy. Seller’s market right now, wait lists over a year. A winnebago revel is like $175k and they are cheaply built (like most mass produced RV’s). It almost makes those unimog rigs look like a bargain. $300k is a bunch of $ for sure, but those unimogs are serious machines and most of the custom builds I’ve seen seem to be very high end.
I’ve got a buddy who bought one of the storyteller overland vans last year. It was about $150k and the build quality is pretty good. It’s the one van I’ve seen that is somewhat mass produced and reasonably priced, but doesn’t seem like the typical old school RV build quality. If I had liked the floor plan and size, I might have gone that route. You’d spend over $100k building something like that yourself and it would take hundreds of hours of labor. The empty van alone is ~$70k before your start building.