The other problem I encountered, was that my feet weren't ready for that much barefoot walking. After a few weeks, I had some persistent pains in the arch of the right foot and I went back to wearing more supportive negative heeled shoes. I need to stretch and roll/mobilise my right foot on a tennis ball a lot more before I put that much pressure on it again for that amount of time. Katy Bowman's "Fix your Feet" DVD is one of the programmes I follow to regain foot mobility. Have a look at a trailor.
I found some Bama shoes - Schuhe wie Barfuss - in my mum's wardrobe which didn't fit her well and adopted them. They are cute and very thin soled. Unfortunately there is a little heel at the back.
I also tried out the Swiss kevlar socks last time I was in Austria and they are fine but very fiddly to put on. I didn't wear them lots but went completely barefoot instead.
If you into sewing I very much recommend making your own barefoot shoes out of sturdy material. Send me a photo if you do.
Oh and a little aside, I have figured out what to do with one of my last pairs of high heeled shoes - mules that I wore throughout my pregnancies. They are now my very own garden clogs - ideal for getting into a full squat with neutral spine while weeding and planting.