I have not been a huge fan of Surly's, and a lot of other touring-specific rigs like the Silk Road because the frames are such incredible overkill for me. I am 6'1" and 160lbs, and my gear is about 9-15lbs, plus food and water. I never break over 200lbs total and these bikes are designed for 150lbs more than that, so they weigh a ton. The two previously linked bikes were 32 and 34 lbs respectively, and surly's all push 30+. The bike I'm looking at, a Giant XtC 29er, is 27- that's like bringing one less 4-person tent on the tour.
A really lightweight and fast 29er would lend a cyclocross experience to the tour. I can dig that.
Hammocks are so divine. I use a Hennessey Hammock and I love it- the great night's sleep is a huge plus. I will either do some heavy orienteering to stay within trees (with 22 feet maximum on distance, I usually find a setup, and the trees can be the width of my arm and still hold me.) I will practice tarp-tenting using the bike frame and the rainfly to see how that works. Insects might be so brutal that I'll need a tent to keep them away from my body anyways. I wouldn't mind picking up a tent. But the hammock... Aww!