That would be super cool. Anything publicly available to look at?
Freescale's Freedom boards are so cheap, so capable, and have such miserable tooling (mbed, DIY usb, Processor Expert, CodeWarrior, ugh)... I wonder if Rust could make them attractive.
I just know that people come into IRC, and there was some discussion about bitfields to help support embedded stuff. Not sure there's a lot written about it yet.
I don't know about 'taking over' but there are some people who are using Rust for this use case.