So I have been looking around at ways of reducing the cost (both initial and operating) and weight of my design. I'm trying to stay away from AvGas powered engines for a couple of reasons (predominately pending demise of 100LL) and have had a hell of a time finding an option other than a turboprop, a diesel or one of those odd modifications of a car engine (which I am staying away from because I don't see unleaded gasoline as a viable option either). The maintenance costs on turboprops are too high to make that an ideal choice which leaves me largely with diesels as a possible option.

However, I am not having much luck finding one that is over 200-300 hp. Deltahawk isn't offering anything, it appears Lycoming has given up on their development of a diesel powerplant and I'm not finding much else that seems useful. Anyone else aware of anything else out there (or in the very final stages of development) that might be an option?