Lots of companies/organisations use Perl extensively on sizeable projects - the BBC, LoveFilm and GlaxoSmithKline are 3 I have personal experience of.
One thing that puzzles me is that PHP seems to be the standard web development language, even at enterprise levels. I can appreciate it is perhaps easier to program in, but the fact that its performance seems to be some way behind Perl leaves me mystified as to why it is a choice for large scale projects.
I develop in Perl and PHP, finding that the former jobs are less available but more demanding and more rewarding, whilst the latter keep my bank balance afloat till the next Perl job.... :-)
If any of my proposed solutions have minor errors, it's because I don't waste my genius on trivial matters. :-P