A good lawyer might be able to find enough ammo to impeach these jurors own admission in their pre-trial questioners.
I think that once both sides accepted them as OK to serve in the jury those questions are moot. However, IMHO, if they can be shown to have lied in order to be selected you'd have a case.
On the other hand, it seems to me that the immediate "where's Rove..." press conference following the verdict would be grounds to start an investigation into annulment.
(What the hell was Libby's defene team thinking?)