I've finished, handed in, and now uploaded that essay I was working on, on reduplication in Siouan. The main conclusions were that:
* Proto-Siouan-Catawban (and Proto-Siouan-Yuchi, but not Proto-Macro-Siouan) productively formed pluractionals from verb stems by full stem reduplication. Every branch of the family exhibits reflexes of this process, although these have often been affected by semantic extensions and morphological contractions.
* Stoney "adversative" reduplication is most probably borrowed from a Salish language.