Yes I just use general "crud catcher" style front fenders/mud guards but obviously look for ones where they are not obviously molded for round tube use but will fit flat on the 4000's square down tube.

That's a KF on mine:
http://www.ukbikestore.co.uk/product/31/mg088/kf-dirt-catcher-mudguard.html

The Zefal Deflector FC50 looks like it may have a flat mounting surface suitable for the sqaure tube?

Rear mudguard is an unamed Chinese job!

Col.