Anyone remember the Zoche aerodiesel? It was a radial that was certified any moment, 10 years ago... I think it is safe to say that any new engine development takes a long time, and requires massive amounts of resources. Just look at the SMA diesel, it may be in production but in limited numbers and as yet no company has offered it. I guess Maule is the first to offer it on the market, not counting retrofits.
My point is, it'll probably be a while before we have Diamond diesels in out Diamonds, and the fact is the Thielerts are already out there. I'd be more surprised if Diamond offered to upgrade completely as compared to replacing 99kW with 114kW in an already existing solution.
But, alas, the thread was talking about the DA50. I hope they stick a diesel in that and apologies for drifting off topic. Looks pretty sweet to me.