I have given some thought to getting a Surly Karate Monkey and trying an Internal Gear Hub on it....seen one on flickr that got me thinking it might make a nice setup. Just bought a Redline Monocog 29er frame and fork to build up over the winter and play around with. Check out Singular Cycles http://www.singularcycles.com The Peregrine model they have looks pretty sweet actually all their bikes seem pretty well thought out.