I've heard her speak several times and met her once; she was not "stiff as a board" then. Her speech last night has been described as "Kathleen Sebelius' national political coming out," I would be nervous too! I think it is safe to say that we will be hearing her name a lot more in the national arena.
Let me leave you with this; she is currently serving her second term as governor of the state of Kansas, which by a large majority is a conservative, red state which IMHO speaks volumes about her.
Cheers,
Bill