It's UNANIMOUS. The 2007 winner of the Laura Ingalls Wilder Medal is James Marshall. This bronze medal, as described by the ALA, honors an author or illustrator whose books, published in the United States, have made, over a period of years, a substantial and lasting contribution to literature for children.
Roger Sutton writes about awarding James Marshall. Mr. Marshall was interviewed by Anita Silvey back in 1986: