I just got a quote from a local contractor:
4" stone, 4" concrete, 6x6 10/10 wire, 6 mil vapor barrier is $4/sq ft. If I made the concrete 5" thick his price would be $4.45/sq ft.
That's a little better than $11.50/sq ft quoted by the barn builder! /forums/images/graemlins/ooo.gif
Now I just need to find a good barn builder with a decent price.....