Some years ago I did a bunch of barefoot running on rubber running tracks. I had some blistering from that, but otherwise it's okay. It feels great. I wouldn't go on roads and trails; that's just asking for a nasty cut and infection. With time, you probably build up some thick skin from that which protects you.
If you want an almost barefoot like experience, just get very light shoes, like middle-distance spikes, and train on tracks some of the time. Then do your long, easy miles in cushioned road shoes like a normal person.
By the way, my father recalls seeing Abebe Bikila win the 1961 Košice Peace Marathon, barefoot.
http://en.wikipedia.org/wiki/Ko%C5%A1ice_Peace_Marathon
