It's worth pointing out that CPAN will also not allow a "get" of a module in a dependency chain ...

Not true.

Here's a quick way to verify dependencies (even circular ones): There's two modules on CPAN with the sole purpose of defining a circular dependency between each other: Acme::Prereq::A and Acme::Prereq::B.

Acme::Prereq::A depends on Acme::Prereq::B and vice versa, see Acme::Prereq::A's Makefile.PL:

    'PREREQ_PM'    => {
                         'Acme::Prereq::B' => 0,
                      }, # e.g., Module::Name => 1.1
[download]

Try it out, it works fine:

    perl -MCPAN -eshell
    cpan> get Acme::Prereq::B
[download]

The CPAN shell's get command will fetch the requested module's tarball without checking dependencies.

However, if you've run into a recursive dependency within a CPAN session, CPAN.pm will keep complaining, even if you switch to get. Restart the CPAN shell to get back to normal.