The peritextual has always interested me. Thank you for talking about it.
Meg is right on about the importance of D&D 4th Edition illustrations showing both male and female characters, and I feel like they did a good job making the women look ass-kicking and attractive without being -too- cheesecake-y.
For contrast, take a look, if you dare, at the revised AD&D 2nd Edition Player's Handbook (the version from 1995). How many female characters do you see in there? Six? MAYBE seven? (pages 78, 85 [?], 112, 149, 162, 211, 286) In a 320 page book? Are any of them kicking ass, particularly? And not a single one in the race or class sections? Seriously?
I think the revised DMG was a little better about this, but I can't bring myself to look at it right now. :-\
If peritextual elements are designed to tell me what sort of game I'm "supposed" to be playing, then TSR was telling me that women shouldn't be allowed to kick ass. And that's just not my kinda action-adventure game.
I've always thought that the illustrations in this book and the revised DMG were a step down from the 1989 editions...