Can't wait to see the UDF concept.
I firmly believe if you can come up with a M0.75 - M0.77 @ 30,000 UDF you will have a winner - especially if it is rear mounted away from the interference with a super critical wing using a counter rotating design to remove swirl effect. Something along the lines of the GE36 UDF might be workable (although a little small for you as suitable more for the 100-160 seat range) Side benefit is lower cabin noise, high propulsive efficiency and excellent specific fuel consumption.
Might need some good software or access to a wind tunnel for optimum location free of interference/other airframe effects at all AoA.
I am sure your fresh lateral thinking is going to take you a long way.
Cheers.
Last edited by an3_bolt; 4th Apr 2008 at 11:21.