So, my *new* question is, (and I've got the hardcopy of the mod perl book so if theres a chapter I need to read, just point it out)
i'd read the book - sit down and spend 2-4 hours skimming through it. all of your questions are answered in it, and it explains the architecture much more eloquently than you'll get off this list.
a lot of what you're asking ties to the fundamental architecture and design of mod_perl -- the books explain that really well, and will give you a lot of insight into why things behave the way they do.
