I suppose Media Create or Famitsu would not track DS electronic novel titles sold in bookstores. I always wonder if Iriya no Sora did okay. I believe Media Works shipped their titles to both game stores and book stores.
Iriya got a sequel, but the first one didn't finish the story so it doesn't speak much about its sales. And with the story already written years beforehand, money would mostly sink on music, SFX, and Eji Komatsu art. Oh, and on that awesome 3 level side-scrolling shooter minigame, Parocaptor SO5.