Mac Mail.app: keyboard "move" folder select?

Hello. On PINE (my old mail program) I could file mail quickly; “s foldername” would file the current message into foldername. (I could even tab-complete!) I would LOVE to be able to do that on Mail.app: a keyboard-only way to file messages. Does anyone know of any way to do that?

(Looked on Versiontracker, googled it; I found nothin’.)