Is there any way we can search for all superdocs on the system? I'm still not completely certain about how the CGI parameters work, and I really don't know if there's any superdoc that only returns nodes of a given type.

nate sez -- you can search with ?node=SUPERDOCNAME&type=superdoc or you can check the Everything Document Directory
N-Wing says: thanks to chromatic, edevites can now also use List Nodes of Type, which lists nodes of a certain type