I have been wondering about a large medium range turboprop airliner for some time.

I know there were passenger carrying commercial variants of the C-130 Hercules, but clearly not very sucessful, compared to jetliners.

How about a stretched EADS A-400?

Are turboprops more expensive to maintain than turbofans?

I would fly in a civilian A-400 airliner rather than an equivalent jetliner if I knew it was less damaging to the environment.