Eco motors -- 80/100 hp diesel
 

This might be suitable for a RV-12 or similar:

http://www.eco-motors.com/Index.htm

Yes, it's not ready yet, but at least they didn't come 4 years ago to say they have diesel for an aircraft -- they really have done something during the years. This is an interesting choise for it's size for sure.

whose engine are they using?

saw their website.. sounds like a familiar story... price is an issue... at nearly 28,000 USD for the whole package... it's a bit on the high side :)

Cast-iron block......belt-drive reduction........turbo weight and complexity .......no thanks! Besides, in America, diesel fuel and Jet A costs more than car gas / Avgas.