I like Ambinder's take on this. Force the bonus recipients to fight for their money, which will put their names in the public domain:
What's the worst that could happen? The "bad guys" -- the derivative traders -- would take AIG to court. But forcing the traders to sue for the money they don't deserve turns them into the villians here, as they'd be named plaintiffs. In all likelihood, AIG would, at some point in the future, settle many of these lawsuits, but not until a good number of the plaintiffs were shamed to the point of dropping a chunk of them.
You might run the risk of intimidation and threats against these people. But that might be a risk worth taking. And seeing them publicly shamed and blackballed from polite society would certainly be some consolation if they do walk away with their dirty lucre.