I forgot to mention SEIFR is only allowed for cargo and there's only one company making use of it in Sweden. It still requires two pilots and special training. I'm not entirely sure of the reasoning there.
The old piston refurbishment idea is an interesting one, and something I've thought of myself. It would be really interesting to see a comparison of DOC for say a Cessna 414, versus a Meridian and one of the new jets.
Perhaps even more interesting would be the seat cost per mile.
If anyone has any figures that could be used for this comparison I'd be greatly interested.