Its an interesting question...

I've got an 1100GS at home in Australia and have just finished a two week 7500Km trip through the centre of Australia. We stayed on the pavement, and I regard the 1100 as way too big and heavy for me (175cms, 65Kg) to take off-road. Great on road though.

I've done a lot of miles on a variety of BMW F650s in New Zealand, two-up. Most recent was in January on a new F650GS P/D 4000Kms. It handles two up with ease, is comfortable and a delight, but the Dakar was too tall for me, and I would not be happy off-road on it either. The regular GS is fine.

But...I own an older BMW R100R which lives in Canada. I've ridden it all over the US, Mexico (east side to Yucatan), and last year rode the Alaska highway to Fairbanks and Anchorage. Its 56000Kms have all been put up in touring the US and both the Rockies and Eastern Canada. The other two run rings around it and yet its almost certainly the bike that wins on a points basis.

It wins in all the areas that count, light weight, can carry load without problem, low height, very comfortable, easiest to handle in bad conditions (eg. muddy construction on Alcan). The low down torque makes it so easy to ride, and its gait is so relaxed, which may be more important than is sometimes realised on long tours.

Finding a good one may be a problem.

cheers
Peter