In reply to ow arm:
The most minimal road shoes I have seen and used are the Vivobarefoot Evo Pure, the soles are 3mm thin and wow do you feel the ground. Which is very interesting as I do daft things with my feet if I can't. They are lovely and light though. Look nice too.
But I do pretty much all of my road running in their Achilles sandals.. but that just might make me a bit.. weird.. But the are slightly thicker, feel more protective but being a sandal it means that they don't make my toenails hurt.
Hope it helps.