For some reason I had concluded that her brother was her twin. This is absolutely not the case. If there really were twins in that family, as I understood from my childhood (altho nothing else from back then is turning out to be true, so why should this be?), the remaining candidate would be Earl and I may never be able to figure that out for sure.
In any event, the brother's birth certificate did not appear, even though his death certificate did appear and his death certificate asserts his birth in South Dakota on a date within the period they searched for his birth certificate. On the other hand, vital records in South Dakota before 1920: don't expect too much, right?
While this is certainly not a cheap way to do genealogy, it is somewhat satisfying. I'm currently awaiting a Washington state birth certificate that I may or may not blog about if I do receive it (I certainly will blog about it if I fail to receive it because I'm curious to see what they say if they don't send it to me).
I think the next thing to go after would be my maternal grandmother's divorces, two of which I believe would have been in Washington state.