The New Balance Nimbus is as close to barefooting as I would dare tread. At $100 though, I'd probably be better off just going barefoot. One of my college friends -- half ninja, half hippie -- had such calloused feet he could walk through broken glass -- not really a skill I have much interest in picking up.
On a side note and after reading your latest blog entry: I had the priviledge to go on a couple of rides with a World Cup racer for Giant when I was living out in Utah, and he talked about getting stuck in traffic jams of people walking the technical sections at races and what a pain in the ass it was (and how it was the "roady" type racers who typically started the pile ups).