Aww, you could have PMed me
But don't worry, you're, like, the third person that's asked, and I finally tracked it down. Like I said somewhere else, it was a random background save, but I found it.
It comes from a free WordPress theme called China Red. It's originally from
here, but I saw the preview
here (select "China Red" from the dropdown). And it says on the original site that the entire theme is free for use, so...