Info on the 400:
Model Code - 1989 to 1990 ZX400H and J (track version), 1991 on ZX400L and ZX400M (ZXR400R), 1994 ZX400L4A (limited edition version in WSB colours)
They were sold in the UK up to 2003 & therefore probably Europe.
I have a 2002 Australian Kawasaki catalogue & they're not listed in that.
A lot of the bikes in the UK are imported unofficially from Japan as the 400 is a popular size over there. They were & still are mostly raced over here & were supposed to be a match for the Honda 400 race reps, so finding an unmolested one might not be easy.
There is a small company that specialises in importing Jap 400's & parts, though it may be better to locate one to ship direct from Japan.
They are called Riders - http://www.ridersmotorcycles.co.uk/