Hi,

you asked for examples. One popular is www.booking.com hiring new perl developers regularly. I'm pretty sure this is a big web app.

My opinion to your questions. You say you love perl: Stick to it. If there are no strategic reasons to choose from a programming language, than it's best to take the one you're very productive in. And be sure, you have to learn much web app stuff. So you'll be happy not to learn the programming language as a building block.

Best regards
McA