This is very good idea. I am planning to replace ububtu-based images I am using now with something smaller, and Alpine looks promising.
Is there any progress? It would be very useful to have official Docker image with rustup installation.
I'm also wondering is people have tricks using rust with docker. With cargo vendor I don't have to re-download everything but I have to rebuild everything every time. Also I think cargo vendor is only for crates.io dependencies not git and path dependencies.