So I think we can all agree that there should be a blog dedicated to children's book endpapers. It's just a matter of time until someone more qualified than I, someone with a bigger scanner (or a bigger readership) starts one. In the meantime, I'll do my best. And take recommendations.
The endpapers above are from Albert the Fix-It Man by Janet Lord; pictures by Julie Paschkis (Peachtree, 2008). They remind me of something the Rockwells might have illustrated (The Toolbox, maybe?). The black and white is a nice contrast to Paschkis's clear and bright interior watercolors. And these are actual endpapers, printed on a heavier weight paper with a matte finish. This is a very nicely made little book.
The endpapers below are from Sandy's Circus: A Story About Alexander Calder by Tanya Lee Stone; illustrated by Boris Kulikov (Viking, 2008). Also black and white, with a sketchier line; the endpaper art is from the book's first double-page spread (it's a wall of the Calder family workshop). The same sketchy black and white drawings appear to great effect in multiple places in the book, overlaid on full-color art. Note especially the rolls of wire, which Calder uses to make his miniature circus.
We just happened to have these two books out from the library at the same time (I love it when that happens). Any other tool-themed endpapers of note?