I don't think the Sprinters are unreliable... but from what I've read from years on this forum, when they break, you pay Mercedes prices for parts and labor.
tatest hit on something: When looking at the size of the older class "A"s, that had fully self-contained rigs in 22-24 feet... Even shorter ones are doable. As far as I know, the shortest is the Winnebago VIA. It would be nice to see something based on the E-450 chassis, and in the 22-24 foot range, similar to the old King's Highway class "A"s of yesteryear.