Amazing post, specially for someone, like me, who is both a fan of Maison Ikkoku and Studio Sharaku. Part of the doujinshi looks like Rumiko Takahashi herself has drawn it.
"hirofuru" also posted parts 1 and 2 of the same series recently, but it was removed, I don't know if he did that himself or if the moderators did it...
Also I agree with Floripes that much of this series really looks like Takahashi's work.