There are two big deployments and some smaller ones. The two big ones are OpenDNS and Skylight.io.

We don't recommend it currently, but some people are just eager. :)

I would venture to guess that those organizations feel that the pains of working with a prototype is worth the payoff of shaping the final product (not to mention the immediate advantages of rust's already stable safety features).

Yup. I know much more about Skylight's case, but this is exactly true.

Some people like to live dangerously.