Jack - thanks, that 151" number is helpful! I've got that to play with.
NotEVen - I like your stick concept. Basically did that out in the desert this weekend by jackknifing the truck and then plotting the arc of the longest leg of that triangle you reference at 5 degree intervals. With the extended pin box nothing crossed a line 48" from the pin box until I hit 90 degrees, so that's encouraging.
I'm thinking this is all going to come together and I'll be able to squeeze a drom and the Smart on the deck and have a safety margin for those tight turns over a dip in the road.
It's my experience that a Class B is not big enough for two people to go full time. But it is big enough for one person if it is well designed. jcussen's link included a Winnebago Ravel with a 5 gallon cassette toilet. That would not do for me.