Hi droid_ca,
A fast few 'cents' on it your Vardo size ?s.
I think the Vardos are really interesting too. Google the word
and check out the various web sites on them, especially the
British sites. My favorite style is the Reading style that has the
outward slant on the walls. Also Google/check out 'shepherd huts' -
a related type of very old-style movable small dwellings, again mainly
British.
Steve Cox did a real rice TD/TTT style modern version of a Vardo.
Check out his build and album on it.
The sizing of one would depend on your tow vehicle of course, but
smaller and lighter is always more economical.
As far as 8ftW x 20ft+L x 12ftH goes, that would be a really big and heavy
unit and would be more time and material and $ consuming. The hgt
you mentioned would possibly make it top heavy - depending on
how it was designed and built of course. Think of how side winds affect
big rigs!
Building one with a lot of height on a hay wagon style chassis wouldn't
really be very practical for traveling unless you're using horses for the
motive force and traveling really slowly. A more modest one built on a TT
chassis with a lower height [6ft6in to a 7ft interior] & CG is much more
practical.
Here's a link to a site I ran across recently on the Tiny House Blog. The
business owner is new at it and fulfilling her dream it looks like, but the
Vardo type she is building looks quite nice. I think it is more suitable to a
semi-permanent set up though, not traveling.
http://www.hornbyislandcaravans.com/
I have no personal experience at it , but from what I've seen/read,
towing a four wheel hay-wagon style chassised trailer -even if the front
wheels can be steered - is not a very fun or safe proposition at highway
speeds. Plus backing is a problem too. Also one characteristic Vardos
don't possess is being aerodynamic.
Here's a wildcard for ya: I've always been fascinated by the various
double-decker trailers of the 1950s. Here is a link to one of the smaller
ones - relatively smaller that is - as double-deckers were intended more
as residences than travel units. I always thought it'd be neat to try and
make a smaller version of this 1953 Lightehouse DuPlex Double-Decker:
http://www.cannedhamtrailers.com/lighthouse.htm
Stranger things have been done I'm sure. I've even played around
with some doodling designs on it myself. I think it'd be quite possible to
do if real attention was paid to limiting the possibility of tipping over. The
Lighthouse DuPlex worked well enough it looks like, and double decker
buses have been around for years, so it can work, we'd just need to
checkout how they deal with that situation.
Just keep on researching and you can come across all sorts of interesting
and useful ideas and information on what you're wanting to do.
Cheers,
Norm/mezmo