iThinksew.com... heard of it?

I just discovered this place by chance.  Browsing through their patterns, I saw a little clutch I had to have.

Isn’t that adorable?

But then I had to go through all the patterns, and I found two SHOE patterns!  These are so cute!

The one on the left is “Annie Women’s Mary Janes”, and the one on the right is “Woman Kimono Shoes”. 

I can see these being more addictive than purses and totes to make!  The patterns call for fabric soles, but that brings me to my question.  Does anyone know where I might find slipper soles sold that I could use instead?  Leather, suede… anything that might be worn outside.