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A better site for Bianchi would be www.bianchiusa.com. As was stated, they offer a couple of the trendy alu bikes with the carbon rear end.
The idea with the steel/carbon Lemonds is that you get the vibration dampening from the carbon seatstays, plus the weight savings with the additional use of carbon in the rest of the "cockpit." Having seen a new Buenos Aires up close and personal, it is an awesome bike. The fabrication is excellent in terms of the joining of the carbon cockpit and the steel spine, and they're using True Temper OX Platinum steel (the stuff Waterford used to make the first sub-3 lb. steel frame). Those that have ridden it said it is awesome; I can't wait to try it for myself.