This is a problem that a lot of people are working on - I doubt it's worth it to roll your own. That said, rolling your own in perl might be as easy as use CMS;, but I doubt it.

Here's a list of existing CMS frameworks and platforms. Not on that list, but written in perl, is twiki, which seems less ... uh ... industrial than some of the solutions, and since its perl, you'd be able to customize it to fix your needs.