Whew... that theory is out there. The main problem is that we're not sure the Sharingan can manipulate the bijuu. When Sasuke went to Naruto's "inner space", it didn't seem like he was able to control Kyuubi, only to send him away. He did manipulate Manda later, so maybe it's just a matter of using more chakra?

Another thing to consider is that we know there's something fishy with the Uchiha clan (there was an entire disussion about it some time ago) regarding the true origin of the Sharingan. I can't remember the link right now, and maybe it was on a different forum, but... the theory was that Itachi had other motives for killing his clan besides his standard lame (IMO) excuse that he wanted to "test his container". But, I like your theory because it is simple, albeit improbable.