Rainbird on 17 May 2008
There is an interview on GT where a MM dev says that it could be fun to have other developers create maps based on a franchise of theirs, but it would not be on the disc, but rather DLC, most likely from the LPB online/share section.
EDIT: And I don't think this would be the "Sony equivalent of SSBB", but technically anyone could do a R&C map.
