I have a carton cpanfile. on servers on which I have sudo, I would be happy to install the latest versions of my modules globally instead.
do I write a script that removes the 'requires' and uses cpan -i (although I am concerned that I may have too many to fit the command line limit), or is this functionality already somewhere else?
If there is a cpanfile you can just run
$ cpanm --installdeps .
as root (with sudo) in the directory with the cpanfile and cpanm will read it and install your dependencies to whatever Perl is configured for this cpanm.
You can ignore carton for that completely.