Cool, except that with cpanm I often install local distribution (cpanm Foo-Bar-1.23.tar.gz). Perhaps the completion can look in the filesystem first before firing API request. Also, might be nice if there is some caching because it seems to be slow (at least from where I am).
This module is incredibly simple and makes installing long-named modules a breeze.
My one complaint is that there's no reason this should be limited to cpanm -- it would work for regular "cpan" too. I'd like it to be more configurable -- let me customize the commands that I want CPAN module completion for.