Many of the active outdoors people I know (mostly mountain bikers) are superkeen on converted Sprinter vans. I think as more active boomers retire, there will be a resurgence of small RVs.
Winnebago just introduced a new model - the Revel - for people looking to travel/live like this. I'm not sure how Winnebago is getting enough 4x4 Sprinters to build them, as Mercedes apparently wasn't prepared for how many of them Americans are buying.
I don't really care for the floorplan, but the concept is attractive - being able to travel off the beaten path, irregardless of the weather conditions.