I just discovered this thread after over two years! The idea sounds really interesting, but...
You take a female mold using plaster of paris bandages.
Once the plaster is dry, how do you take your feet off the mold? I can see two possible method, none of them seems to be acceptable:
1) Destroy the mold, obviously not the point...
2) Cut the mold into two halves with an angle grinder, which is certainly not the safest thing to do so close to your skin.
I'm eagerly waiting to see photos of the final product! Does your feet rest directly against the carbon layers, which are, basically, hard plastic, or did you use some kind of more comfortable inner layer?
A