Another article:
HELI-EXPO: R-R lifts veil on Eurocopter "X3" high-speed prototype - The DEW Line
Interesting that these images have swept wings (and propellors - strange mix). This may just be to cover themselves for future development. Then again the technologies you need to consider transonic are swept tip blades and servo flaps (leading and/or trailing). We live in interesting times...
http://www.pprune.org/rotorheads/417...urocopter.html