I don't know of any off hand, but I'm sure if you cruise amazon.com you may find some. I think I may just do that myself.....should be interesting to see if there are any. If I locate any I'll be sure to share with the group!
Ahh found quite a few on BarnesandNoble.com
Click on Books, then Children's and in your search window specify: bi-racial children and about 2-3 pages of books appear. Good luck!