Tubeless tires sound like a good idea, the weight of tubes is material. However, wheels are often the center of trouble, and you need to be able to change spokes. So for now, I don't see the practicality. I would need something simple like nipples that sealed with O-rings, and tires that did not require a lot of slime, to want to go that route. 2.2 is a fat hog of a tire, and some people do prefer them for general touring. Myself I have yet to see the biketrail as opposed to back country tour, that could not easily be ridden on 1.5s , and there is a huge reduction in weight. In fact I ride slicks on stone paths, etc... This assumes there is pavement involved also.
You can go ultralite, and preserve a certain degree of the feel of an unloaded bike. However, it doesn't take all that much weight before a bike is not really usable like a bare road bike or even an MTB. So while one might think that a heavier bike would need the fat tires, it often turns out that light tires are better. You aren't going to be grabbing big air, doing drops, or successfully running mud holes on a loaded bike. So keeping the wheels light and moving may not really require the big wheels. Or it might...
Last edited by MassiveD; 03-16-12 at 03:23 AM.