There are still major problems with props and diesel engines. Only steel props will work at this point. Very heavy. There are other issues as well that Teledyne nor CMI want to talk about publicly. They want to look like they think the public wants them to look--that diesels are the wave of the future. I am less than convinced. An unleaded AVgas will arrive and the diesel rage will wane.
Diesels in airplanes are like fitting a submarine with an air-cooled engine. I guess you "could" do it, but why would you?