Maybe, but I would not go for it.
Three wheels as a mild adventure machine makes sense. Dirt roads and gravel roads. Anything more offroad and as mentioned that rear tire will be running down the center stripe of a trail. I you have ever ridden a dirt bike on a trail like that, typically the center has all sorts of debris or holes and such. Myself, I am always on full alert if I need to "change lanes". Heck even on the mtb I will simply crossover to the other track.
From a handling standpoint, wouldn't the machine be the mix of a sled with wheels? I would expect a huge amount of body movement unless simply rolling along. and being much shorter coupled than a sled may spin easily.
In the end, I would expect the market to be small and limited. Could be good for some, or maybe persons unable to ride a two wheel machine. Then again, with the size, cost and performance of the side by sides, I could be way off.
Adventure bikes are cool and all, but seriously, they sometimes convey in advertizing this go anywhere concept. With the right rider that may happen, but honestly the are pigs to ride. Heavy and unless the terrain is open, slow and a workout to ride. I have ridden my friends LC4 and it was no dirtbike. Get it stuck and you better be riding with friends or have brought a winch or comealong.
If you want to use the machine to travel on dirt and gravel roads they are fine.
Dual sports have been around a long time. They are limited by how much you can carry. These however are much lighter and able to be ridden on more serious terrain. Done right, the dual sport can carry a some stuff, but certainly is not best with box panniers on the back.
Unless you are retired or well off, most people would be riding maybe for a weekend the majority of the year. Anyone doing a true adventure ride, knows it takes many days of riding.
Currently I have the hots for a Husqvarna FE 350 S. Looking at some other machines also, but when the Adventure fad dies, these will be the next big thing. A performance oriented dirtbike that is street legal. Problem is, Husqvarna knows what they have and price it like gold. I would like to ride the Trans America Trail at some point. Do it semi supported where my dirt bike riding friend and I ride two wheels, while at the same time, his wife carries the stuff to their Colorado home from Florida. Trailer the bikes to Tenn, then ride sections and meet up at night until we hit their home in Colo.
http://www.husqvarna-motorcycles.com/en_us/enduro/fe-350-s.html
PK