Great Bridge did essentially that years ago, but I think we only got away with it because we didn't say which DBs "Commercial Database A" and "Commercial Database B" actually were. Even off the record, we were only allowed to tell people that the commercial DBs were Oracle and SQL Server ... but not which was which.
IMHO clues like:
"What versions of the databases did you use? - PostgreSQL - 7.0 release version - Proprietary 1 - 8.1.5 - Proprietary 2 - 7.0 - MySQL - 3.22.32 - Interbase - 6.0 " and "PostgreSQL" and "Proprietary 1" was running "red hat linux 6.1" and "Proprietary 2" was running Windows NT server 4 - service pack 4" in articles like this one: http://www.xperts.com/news/press1.htm
helped some people narrow it down a bit. :)
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