The bit about "Perl Design Patterns" seems closer to that mark, but again it's just showing some implementation examples to people who are already mostly familiar with the concept of Design Patterns.

Knowing how polymorphism can help you clarify your design is something that takes hands-on learning. Knowing the theories about messaging, and encapsulation, and accessors, and the difference between aggregation and inheritance, will only take you so far.

I suggest you pick a problem which needs solving, and solving it yourself. Repeat this cycle a few times. You can read a cookbook all you want but you can't learn to knead bread until your hands are intimate with the eggs and flour. Your first loaf won't be a success, either.

(Update: I wrote this assuming that you're not familiar with OO because you're asking about OO-perl. I based this on the assumption that those who know about OO are probably going to pick up the perl-specific basics of OO-perl in about a day, and won't really fret about it that much.)