Not possible at the moment. I think it is tightly integrated within all the internals of how the phone handles input. That includes the T9 Quicktrace, word prediction, etc.
developer.bada.com/badaforum/board/thread/view.do?boardName=bada-general&messageId=29089
Even from the sample codes, you call the keyboard with parameters on how it is displayed, 12-key mode, qwerty mode, qwerty url address mode, etc.
dpimg.ospos.net/contents/docs/apis/bada-V1.0.0b1/classOsp_1_1Ui_1_1Controls_1_1Keypad.html