Before I just go ahead and put a really awful check constraint on the Catalog table, I wanted to solicit some better ideas first.
I want to ensure that all shared data sources on our report server are deployed to "/Data Sources". Every now and then, we get one mistakenly deployed to some other directory (particularly if it's a report upgraded from SSRS 2000, which didn't allow specifying a different data source deployment location).
I can put an ugly check constraint on Catalog (Type != 5 OR ParentID = 'GUID of /Data Sources directory', or similar) if it comes down to it, but if there's a better option, I'd rather use that.