Theres a lot of factors involved in bike sizing, but I highly doubt at 6 feet you'd be on a bike with a 54.5 TT unless your arms/torso is super short compared to your legs. I am 5"11 w/32 inseam and my cx and road bikes have 56 and 56.5 top tubes and 110 and 120mm stems respectively.
I'm with BSUdude
I'm 6'2" with a 31" inseam. My cross bikes are usually the same size as my road bikes but I'll run a 10-20mm shorter stem and might run the saddle a little lower - 5mm or so. I rode a Giant TCR m/l road bike for 2 years and that would have been a great cross size for me.
Hope that helps a little