my familiarity with boats is limited to 4 years living on a Vagabond 47, and my own Catalina 30, and a few charters.
At the last boat show, however, I spent some time on a variety of Catalinas, and all of them have pretty good headroom.
I'm also 6'4.5.
My boat has about 6'4 of headroom, which I think is phenomenal, given it's a 30'. But the caveat is, where?
You aren't going to have 6'7 headroom from bow to stern, regardless. I'm happy standing straight, anywhere.