I've wondered if BMW would build a F800RT. Personally I think it has the potential to be a good seller. It would certainly need to be capable of "loaded down, two-up touring" but I believe it's main focus should be a little different. And now I put on my "David Robb hat":
The 2010 R800RT will be lighter and less expensive than the R12RT. It will appeal to a wide variety of riders. These will include solo touring, older seasoned riders down-sizing from heavier Gold Wings, GT's, and LT's, women, new touring riders, and commuters.
Adjustable ergonomics to fit such a wide spectrum will include multi position seats, handlebars, windshield,
and foot pegs including shift and brake levers. Built-in mounting docks will allow factory quick-removable back-rest, trunk, tank bag, and full size saddlebags. The muffler will be lowered to allow this. The F800RT fairing will offer protection from the wind and elements similar to the K13GT and approaching that of the R12RT. It will also incorporate storage compartments for your papers, glasses, Glock

, etc. Usable gas capacity is increased to 5.8 gallons. Final drive will be belt. The transmission ratios will be changed. In comparison to the lighter and sportier ST, the RT will have a lower (active) first for starting out, and such times when 2-up loaded down on a steep incline. Sixth is now 6% taller allowing for optimum mpg and more relaxed cruising.