hmmm.... not-lying is moral in the kantian sense. It's often 'moral' in the utilitarian sense, though definitely not always -- as in your examples, or when the proverbial murderer is at the door, asking if his chosen victim is at home.

On top of that, I don't think rationality is necessarily moral. Many rationalists may also be very moral people, but that s not a requirement -- thus, I think there is plenty of room for lying in rationality, whether its moral (by some definition) or not. Often it may be very rational to be moral - but that is not necessarily always the case.