Aliasalpha: Pretty sure that EON Productions are the sole owner of the Bond IP, MGM are just the traditional production partners since they've been in bed together since the beginning. If MGM go down the tubes, EON could just work with someone else
MGM owns the film rights to the Bond Series, and it has since 1981, when it purchased United Artists Corporation. EON Productions, well its holding company, Danjaq LLC owns the trademarks and copyrights. I believe both UA Corp and Danjaq LLC had the trademarks and copyrights, and MGM may have partial ownership of that as well (from when it purchased UA. EON is the production company for the movies, but without MGM, their hands are tied because they can't just go somewhere else.
It is kind of like the situation with Marvel Comics vs. Sony & FOX. Marvel owns the rights to Spider-Man and the X-Men (Wolverine), but Sony (Spiderman) and FOX (Wolverine) own the film rights. Basically, Marvel is screwed when it comes to trying to make a future movie with either of those two brands. Technically it is Disney now, seeings Disney bought Marvel last year, but still, a very similar situation.