If we can't trade tony allen to the Pacers, some team must be willing to take him. He's not horrible. He's just been in Boston too long.
I think most of the teams for which Tony Allen would be an asset are not willing to spend money on a player who has had a lot of injuries in the past few years, has been very turnover prone throughout his career, and potentially has "character issues" off the court.
In a better economy, some teams might be willing to take the risk. These days, though, I doubt it.