Veebyes,
So true on the fuel use!
A couple of our twin 454 cu in gas engined larger cabined power boats would gobble about 3/4 gallon/mile but they would be on plane and going around 26-30 knots. That was before the fuel hit $2.00+ a gallon though at the Marinas. By contrast, our very heavy wide 34' Catalina had a 25 hp 3 cyl diesel and merely sipped fuel as it wouldn't go over 8.3 knots (hull speed) with the iron genny full bore. I know you understand displacement hulls. We're a rare breed as we like and had both stinkpots and rag hangers at the same time. Only live once! Wife's disability and 18 operations wont let her heel any more or be whipped side to side on the bridge so no more sailboats or high boats now. Just low to the water and she does fine as long as I don't let the boat pound. Do what ya gotta do!
On the 65' boat in the pic: I figured there was more or that the 65' boat was used for mostly day cruising with customers and has a huge salon. It's normal for salt water boats to laid out quite differently than the same sized pleasure boats built for the Great lakes use.
Need a Captain to pilot a 65' long vessel and that alone is why many owners on the Great Lakes stay just under 65' as they want to pilot their own vessel. However there are gobs of the 65' to 100'+ private vessels on the Great lakes and many right where we live.