I'm doing an unscientific poll. I am a hair under 5'11 (about 180cm) and riding a 54cm with 543mm ETT. When I look at what other people my height ride it seems like people are riding 55-57 frames. I know that means nothing and also frames are measured differently. I've used the competitive fit calculator on line a few times and the top tube recommendations I get are:
I have tried several frames in the past few years and I've found anything with an ETT over 555mm feels like I'm fighting to get the bike to go where I want.