Speaking of Merckx... I don't know if this is an "ultimate bike" but it is something that you don't see every day. It's a '79 Carabela Profesional, which is essentially the same thing as a Windsor Profesional ("Mexican Cinelli"), except that it was fitted with the original Dura Ace group and not Campy. It was built with Columbus SL tubing by an ex-Cinelli guy at a factory in Mexico.
This one doesn't have a lot of miles on it. I bought it new in '79 and wasn't really a serious rider. It's been wall art for the last 30 years. For sale, to a good home...
JR