For all those who can't read German, here is an English review of the fretless CR5, including sound samples:
PremierGuitar
Interesting fact: two out of three reviews I've read so far falsely state a wooden fretboard it's phenolic, and I think this sheds some light on the psychological aspects of those "no plastic, only ebony for me" naysayers
Bernd
According to the NS Design site, it is ebony:
"The fingerboard is ebony, with a 35" scale and familiar 15" radius. "

