Umm now that I finally found this photo everyone was talking about, I don't necessarily see "tiny wagon" as much as it looks like it could be the unfinished frame of an old-school baby carriage? Again, it's hard to get a perspective on size there and it admittedly looks a little tall for that, but I can't tell for sure.
I would say that a baby carriage could fit more in line with either the speculation of a dolls-centric house or the period piece rural/midwest exorcism house that Legacy mentioned in the spec thread.