I have the same problem. I am 6'4" and living on my boat with only 6' headroom. I started a thread today throwing out the idea of raising the hull
to add the room. Replies so far have been negative on the thread, but mostly because no one has done it and most think it is too much work and cost. I am not so sure about that, but will continue the research
I have also started a conversation with a naval architect and custom boat builder
this morning who was recommended and he thinks it is very doable and will not affect stability too much. He has requested boat pictures and will help me decide if I am to go forward with it.
Granted each boat has it's own unique attributes which would affect this option. Mast
going through deck
or not, how is rigging
attached, are walls all covered with cabinets and wood, etc. Mine has all ideal details for this project
Just something to consider.