Check out Wolf Creek Truck Campers. They are quality build with lighter weight. I'm sure they have a model that will fit your needs. I have a travel Lite that I'm very happy with. They also probably have something you'd like. Happy Camping!
"Confidence is the feeling you have before
you fully understand the situation"
1999 Toyota Tacoma Pre-Runner
TorkLift Tie Downs
2010 Travel Lite 690FD
2007 Honda ARX1200T3D
2008 Yamaha Zuma 50 Scooter
2010 "Blue" Bulldog, "Luna" Camped 10 Days 2012
Lots of options out there, and as BuzCut posted, you aren't limited to rear overhang that much (though tongue weight with a real heavy camper can become an issue).
I did 4000 miles in December/January with this setup:
It wasn't fun driving this setup, but it was manageable. That is an enclosed 24 ft car hauler attached to a torklift supertruss 24" extension and an equal-i-zer weight distributing hitch. And, just because my TC is a pop up doesn't mean it is light. It isn't.
One thing you might want to consider...if you can custom order a TC...consider going with a cassette toilet and using the extra tank space as grey water storage for your post race showers. Some other folks with pop up TC's have done this...and I wish I had the foresight to do it with mine.
I think you'll like Adventurer. It sounds like the 86FB is just what you're looking for. We have the 910FBS and it has tons of staorage (yes it's much larger), but you'll how spacious the 86 is as well. We have to fit 2 dogs + us in ours.
2011 Adventurer 910FBS,Torklift tie downs,Fastguns & Wobbl-stopprs
2012 Dodge 3500 DRW 6.7L CTD, 4x4, LB,CC,6 speed auto,3.73 axle, General 17" on/off road
2008 Lund 1825 Explorer Sport,115 Merc,9.9 kicker,Torklift Super Hitch,42" Supertruss
USAF ret E-9&E-7