Here's my plan:
We take the 27 Hp, 3-cyl Yanmar outa the boat, we turn a new Chrysler Pacifica into a diesel Electric Plug-In Hybrid.
You could just do a BAS system on that. "belt alternator starter". The starter is replaced with a belt-driven alternator that can also act as a motor to start the car. The engine shuts down when you're stopped in traffic, just like a full hybrid. Supposed to get a 2 to 5% city fuel economy improvement, and not that expensive to implement.