Most of the major manufacturers nowadays will have road bikes that are more race-oriented and slightly more comfortable. In most cases, the differences are rather slight. E.g. the shorter head tube only really matters if you are looking for a super-aggressive position.

I don't know the Trek lineup well, but I'm fairly certain if you tell your favorite LBS that you're looking for the equivalent of a Specialized Roubaix or a Giant Defy, and they should be able to show you the Trek equivalent.