I actually found time to work on Mastering Perl in May, although not enough time to talk about it. Who wants to take over everything I do, and do it for the rest of all time?
I don't know why it didn't occur to me earlier, or at least why I didn't pick the low hanging fruit, but I need a chapter on taint checking! We wanted one for Learning Perl and Intermediate Perl, but other topics prevailed. Since we try to keep the books around 300 pages (I don't need a rotator cuff injury), we have to cut some things out.
Next up: I have to find some good examples for the chapter on advanced regular expressions.