At London Perl Workshop 2011 there were many talks about CPAN modules and dependencies.
When people talk about "CPAN dependencies", it usually used to come with the phrase "Hell". Not anymore. Everybody talked about more fun things to do with CPAN dependencies, which is probably inspired by the toolchain updates and my own cpanminus.
Especially at lightning talks, Tim Bunce explained his dist-surveyor tool that scans the whole library path and queries metacpan to figure out which distributions you have to need, when you migrate perl to a newer version. It also rebuilds the CPAN mirror structure you can then feed into cpanm's --mirror option (like Carton does).
JJ introduced his own cpackage module, which is extremely similar to what we do in carton or OrePAN do, i.e. rebuilds the mirror index based on the archives you downloaded with cpanminus, and then bundle cpanm itself into a self-contained perl script you can execute on a remote server.
In addition to all of this, I presented the proposal on cpanfile, which is an extracted version of Module::Install's DSL to represent CPAN::Meta::Prereqs. This is still a proposal, but it will be trivial to implement on upcoming cpanm and Carton releases, and this would make declaring and managing CPAN dependencies in your Perl application much easier.