Twin Navion type certificates???

This just has me curious. As a former owner of a single engine navion was involved in a discussion about Twin Navions which in turn led me to wonder.
How many type certificates were Twin Navions built under and second who holds those type certificates now?
Any information or ideas most appreciated
Thanks

www.twinnavion.com

Primarily two twin navions, Riley and Camair.

The Riley type certificate is held by the American Navion Soiciety.
There's still an independent company holding the Camair certificate.

Neither are affiliate with the company holding the single engine TC.