Odin and Bahamut have both officially been given the titles of "Elder" Primal. Odin in his first concept art release in the 2.0 timeline, and bahamut in a LFP shortly after the 1.0 servers went down.

I suspect the Good King Moggle Mog XII is also in this league.

They made it clear that elder primals will not be summonable. Too powerful to be controlled like that.