Don't forget the DA42 is a twin! That makes it all the more amazing that it can be cheaper to run than a Cirrus or equivalent. Avtur may not be cheap in the future but avgas certainly won't ever be cheaper than avtur.
2 engines for the cost of one - brilliant! The Tecnam twin looks promising too, although it runs on avgas or mogas, it'll offer similar economics as the DA42 if marketing is to be believed. It'll likely be even more economical infact because the engines are proven, have low acquisition costs as well as replacement cost and service should be readily available. The arget price is also about 100 000 EUR less than the 42 and cruise performance is only slightly less.