User blog comment:Xilinoc/Ch. 566 (not out yet, but dis gon b gud)/@comment-2211792-20140203180111/@comment-5398287-20140203230756

Shunsui is the only Bankai-possessing character whom I can remember doing that. And even if there are more, that's not definitive proof that only Bankai-wielding Shinigami can do so, whereas Byakuya explicitly stated releasing ones Zanpakutou without saying its release command or name is a sign of achieving Bankai.