You're right about the lack-luster sales of inboard powered boats in the past, but it's interesting how many on CP seem so enthusiastic about them. I still think with the cost of 2 big outboards it makes sense to revisit factory inboard Diesel power option, especially with the newer Diesels available.
I spoke with Linwood Parker at the New England boat show about the inboards and why he stopped making them years ago. He said he liked how the boat ran, and balanced out with the motor further forward, but he said the handling characteristics of a single inboard and to some extent lesser performance steered people toward the more familiar outboards.
It still strikes me to see 30-40 foot boats with several outboard motors instead a one or two big inboard power plants.