i think there is not a market for this. passengers wants to fly with jets. even when the propfan as well some turboprops are very modern and efficient the "Normal" seatpayer does not realize it .
I disagree.
In the US, Horizon Air advertised a complete conversion from turboprops to small jets 8 or 10 years ago. Two or 3 years ago they announced an about-face, and are [nearly] complete with their conversion to an all Q400 fleet.
With fuel prices continually rising (even with short-lived dips on occasion), fuel costs will continue to drive the market. Jets with 60 seats or less are on their way out of US fleets, and the turboprops are making a comeback. The UDF may become practicable with advances in fan blade technology.