Personally I suspect Kakashi's small chakra supply would make him pretty ill-suited for being host.
If he actually managed to contain it it'd be awesome, but it might be much harder for his body to contain the Kyuubi than Naruto's. As a kid he'd even have much less than at the start of the series.
*Tries to take over Konoha once. Loses to a guy who's special ability is creating trees. Flees*
And controlling biju, apparently yanking Kyuubi away from him.
*Somewhere down the line attempts to kill someone whose special ability is creating rocks. Fails. Flees*
Which one was this?
Also, he did take over Mist for awhile and then controlled a later Kage there. Put together Akatsuki, thus stealing 7 of the 9 Biju. And we know isn't exactly at top.
*Manages to kill two relatively no-name high level ANBU. Loses an arm in the process and damn near dies.*
I'll just comment I like how one doesn't have to be a major character to be badass in Naruto. These two clearly were A+ ninja with badass powers, they'd be Jonin easily if they were part of normal rank structure.
Not to mention he was going to kill Kabuto but Edo Tensei pretty much made him shit himself and team up instead.
Though in his defense, it wasn't even all of Akatsuki popping up again that made him worried, just whatever... the last one was. The Akatsuki just made him willing to deal.