I finally tracked down the cover of the book (thanks to a super amazing reader) for Lanie, the American Girl of the Year (GOTY) for 2010, and we know the storylines from her books.
Thanks to a sleuthy reader (Sitara) for sending me the following information.
It looks like the American Girl Girl of the Year 2010 may be African American. The books show up on Amazon without any titles, but the author is listed as Jane Kurtz.
Jane Kurtz grew up in eastern Ethiopia and writes for children based on her experiences growing up in Africa. She is also the author of:
Based on the fact that we have not had an African American Girl of the Year, we have an African American president who has daughters in the target age for American Girl and the books that Jane Kurtz has already authored, I would put my guesses on an African American GOTY with an interesting story!