Well, that certainly was an exercise for the mind. Lots and lots of cools stuff.
My only clear thoughts were:
1) Will Friedl do a "Mastering Regular Expressions" for Perl 6 regexes when they come out?
2) Would it make sense to include a lexer/parser section?
3) Would it make better sense for a separate lexer/parser book specifically for Perl? That way one could showcase the different modules as well as make use of the new regex engine to make gramars.
At least that was my thinking that new regexes make it much easier to produce grammars with the new engine alone and might, heaven forbid, make Parse::RecDescent sort of obsolete.
Lots of fun ideas while I was reading. Nothing than can really be formed into coherent expression but I feel them buzzing in the background.