Hi Kevin,
I've considered something similar. I looked at a bunch of different helm seats, but I think the dinette seating is lacking even more with ergonomics. We have never had a need to use the table as a berth... coming up with comfortable seating there would be a big step forward. We use a pillow behind our backs, since the bottom of the seat area is longer than typical. I'm thinking a custom auto upholstery place may be a good starting point. At this time, I haven't felt the need to tear into it, but it is certainly on my consideration list.
BTW, we were up in Yellowstone last week to visit our friends Paul (Lake Queen Captain) and Pat. Saw your boat, and John's; Jay and Jo-Lee were out and about. I enjoyed seeing Paul's boat - his helm and co-pilot seat were very comfortable.
Best wishes,
Jim B.