I don't know about rites of passage, but IMSHO, you should generally ask yourself a couple of questions before undertaking something like this. 1) Is there a need for it? Is something lacking in Perl and CPAN, that makes this necessary and useful? 2) Is there something that comes close, that you could perhaps work with the original programmer/maintainer/whoever, and add to it?

Reinventing the wheel is fine, if you want to learn how something is done, to see what the issues were in solving the problem. But you're very unlikely to produce, say, a sort routine that will be an improvement on what's already out there. Same thing with templates. They've been around long enough, and have had enough eyes looking for bugs, testing them, etc., that it's not likely you'll come up with anything better. Maybe you would - it could happen. But the odds are against you.

I suggest you think about your own experiences, and times you thought, "If only they had X, it would be so much easier". Then find out if X exists, and if not, make it.