You didn't mention which country you live in, but if it's the USA or
Canada, the only motorhome I would recommend would be one built on the
Mercedes/Dodge Sprinter 3500 chassis, with the 3.0 liter diesel
engine. The industry has only been making motorhomes on this chassis
since 2005 or 2006 so the ink is still wet on the reviews.

There are several manufacturers now building on this chassis and I
examined all of them closely before choosing the Winnebago View /
Itasca Navion (they are the same except for color / carpet schemes). I
get 12 to 17 mpg pulling my glider trailer.

It's kind of hard to "make" (as the original poster indicated) a
Winnebago, but I do agree on one point. For those of us who don't want
to invest nearly the cost of a new glider in a motorhome, a used
Mercedes/Dodge/Freightliner tall panel van is an excellent reasonable
cost base for hacking together ones own mobile headquarters. I'm
waiting for the arrival of the Ford Transit Connect in the US, if it is
spec'd to tow a reasonable amount, I think it will make for a fine
live-aboard tow vehicle...

Marc