I.dont think so, and I'm convinced that this could be done automatically as part of rustc, with the negative side effect of small changes that affect the splitting behaviour causing wild compilation time changes that are hard to debug.
I think that listing behaviour could eventually be landed on rustc itself, but as it happens I am working on a listing tool, so I might just prototype it there first!
The benefit of telling users "you can split this section off to its own crate" is that the "break" of that can't ever be silent.
