in reply to Looking for examples of well-written modules
Let me rectify that.
I personally learned a lot from reading the source to LWP. While CGI is an important module, I can't recommend it as good example of how you to code. Modules written by TheDamian impress, but in a fashion that you're likely to find impossible to emulate. Still read a couple anyways.
Beyond that, if anyone has impressed you (like Simon Cozens), grab a few of their modules just to read it. Afterwards you may wind up more or less impressed, but you'll learn something.
But I still think that the cleanest coding style that I have seen had nothing to do with Perl. It was when I peaked at the source to Ruby by Matz. The addition of maintainance since then (and not all by Matz) might have muddied it.