Are their any true talented 7 foot back up centers that we can trade for this off season in exchange for Tony Allen or/and Scalabrine?

I still hope the C's can add a legit 7 foot monster center to back up Perk and Rasheed, because if either gets hurt we will not have a legit center on the team to come off the bench.

Such a center  will be vital insurance heading into the season and will also come in very, very handy when we have to deal with Dwight Howard and Shaq during the playoffs.

Anybody know of  a list of  talented centers who are currently available this off season that the Celtics may be able to  obtain in a trade for Allen or/and Scal?