Hey there! I have a children's book published in 1978 calle The Oath of Bad Brown Bill which has some insane illustration in it. I'll scan in the book in full (if it fits in my scanner) and pass it on to you. It is unique and Australian.
For your search: both my mom and I read these as little girls: the "Martine" series by Marcel Marlier - see the illustrations in this Flickr group:http://www.flickr.com/groups/347645@N25/