Even shorter, as -l appends \n to all prints:
$ perl -MLWP::UserAgent -le 'print $LWP::UserAgent::VERSION' $ perl -MLWP::UserAgent -le 'print $LWP::UserAgent::VERSION' $ M=LWP::UserAgent && perl -M$M -le "print \$$M::VERSION"
$ M=LWP::UserAgent;perl -M$M -Esay\$$M::VERSION