This is purely speculative rumor, since Quentin Tarantino has said nothing himself about a pair of Kill Bill sequels. But, CRIenglish.com is reporting that Kill Bill Vol. 3 & Vol. 4 have been shaped, and that there is a chance they will be shot in China.
Executive producer Bennett Walsh told the Shanghai International Film Festival that, "The third film involves the revenge of two killers whose arms and eyes were hacked by Uma Thurman in the first stories. The fourth installment of the popular kung fu action films concerns a cycle of reprisals and daughters who avenge their mother's deaths."
We'll believe it when we see it.