CastleMiner, predecessor to CastleMiner Z also sells over 1M units
"I would like to announced today that CastleMiner the predecessor to the all time best selling Xbox Indie game CastleMiner Z has also shipped over one million paid downloads. It was recently announced that CastleMiner Z had shipped over 1.5M paid downloads. Together the CastleMiner franchise has grossed over 4 Million dollars, making it by far the best selling franchise on Xbox Live Indie games."
http://digitaldnagames.com/?p=426