In answer to my question regarding middle grade science fiction on the Child_Lit listserv, Farah Mendlesohn replied with the address of her blog and her book list, dedicated to mostly children’s science fiction. Hooray! This will be a great resource, as will the book she wrote, which is coming out sometime this year.
Now, the book list says "YA SF," but I’m seeing everything from Captain Underpants (how could I forget him?) to Scott Westerfeld, so it encompasses more than just YA. I’ll skim and see what I can glean for the particular list we’re making here, and if you all happen to see any on there that would count as middle grade, let me know.