Thanks very much for the suggestions!
I have been trolling fat-bike.com for awhile now, but haven't seen too much coverage of this question beyond what's been mentioned here. Maybe the Pugs is worth reconsidering. I have an older KM that I love, but am not crazy about the older style Surly dropout setup, as well as the rear offset of the Pugsley. Borealis would be great, but money is always a factor. This would be my first fat-bike.
Anyone know if the Specialized Fatboy can run 29+?