First, there are other threads on bikeforums that talk about this hub; search places like commuting, utility, and mechanics for lots of opinions.

I don't have any touring-specific comments on your proposed build (or any touring-specific comments at all; I'm just lurking here to learn), but I built a round-town sort of bike for my wife with that hub, and the results are less than ideal. I understand they've redesigned it since then so that it's supposed to be smoother shifting, but one thing that apparently has not changed is that the hub is geared really high.

On the one I built, I'm running a 36T chainring and a 25T rear cog and 700x35s, and it's really pushed the limits of what my wife can comfortably pedal. She's reasonably fit, not an avid cyclist, but it's a challenge. I ride a lot more than she does (though nothing like what folks in this forum do) and it's not real comfortable for me either. My regular ride (mainly for 7 miles to work and back) is a Nexus 7 speed internal hub and its range is much more reasonable.

YMMV, but my guess would be that you wouldn't get enough low range on that hub to haul much load around. I calculated all the ratios and gear inches on both and I can try to find that and post it, or you can go to sheldonbrown.com or a number of other places and do the math. Figure out the low-end gear inches on your current bike, determine if you are comfortable hauling a load with that, and see if you can get down there with this hub before you lay your money down. I wish I had.

PS If you still wanna go this route, I know a guy that will sell you the hub built into a really nice wheelset and the Dia Compe 610s!