Is there one?

As far as I know, there isn't any canon ending for the factions. I'm willing to bet that the NCR ending is going to be the canon one, though, so the NCR/BOS treaty ending might be canon.

If there is, you won't know about it until the eventual tie-in novel, comic book, or sequel.

These things aren't usually decided in advance. Only when trying to setup what comes next.

Actually I think that the Yes Man ending lends itself to possible expansion. At the end after siding with Yes Man and he appears at the dam he tells you that he found extra code written by Mr. House to unlock a more assertive personality and that he would be shutting down for a while for the installation to happen. I see the possibility that Yes Man with his more assertive programing might try to use the Securitron Army to try and take over for himself, leading to you having to try save New Vegas from the Securitron Army you helped build and activate.

the yes man theory is a good one, but when you finish with that no one is in new vegas for 5 years or more, so why would you fight over a vacant strip?