While headroom will be an issue I think what you will need to look at more is berth length. I'm 6'1" ,my wife is 5'10" and we had a hard time finding a double berth that would be comfortable for the both of us in a 30'ish boat. Single berths seem to have the length so if you're solo it might be easier. I don't mind stooping a little while going through the cabin but I like to be comfortable when I sleep. Another thing to look at is headroom in the head (no pun intended). The cabin might have good height but trying to pull up your pants in a short and small compartment is a real struggle. Good luck!
P.S. In my experience full keel boats have more headroom than fin keel ones because of the hull shape so you might start there.