Here's Dmitry's second entry, an evolution of his previous "mu" idea.
While working on the mu letter (I couldn't find any greek fonts that I like), and aligning the line angles there, I got an idea that sharp knife-like angles could allude to the well-known idiom that perl/cpan is a "swiss army knife", and from that idea comes the second design, "muplus".
It's the same letter "mu", but the red background and the cross above the letter make reference to the swiss flag/emblem/army logo, so unless the copyright division of the Swiss government disapproves :) you could use it too. Also, the cross can be seen also as a reference to the PerlMonks culture, where karma ranks bear terms such as saint, pope etc etc. Godless atheists like myself could be possibly satisfied with that μ+ is an antimuon symbol, and having some fun time while googling "antimuon Perl", as an exercise to the reader :)