There is a new issue bayonet that is very much like the HK version ,it looks great and I belive it is made by colt but is not the best steel 440A.
BAYONETS EICKHORN®
The above is from Colt (Diemaco) Canadas site. They have a bunch of other knives for the military on the same page here:
The Eickhorn-Solingen® BAYONET The Eickhorn-Solingen® Bayonet System 2005 is in current production and in service with NATO armed forces. System 2005 is the latest generation of the Bayonet 2000 and is a result of close co-operation between Eickhorn-Solingen Limited® and NATO armed forces, the System is unique to Eickhorn-Solingen and permits rapid retro fitting to all NATO assault rifles.
Eickhorn-Solingen® blades and tangs are laser cut in one piece from high carbon steel, hardened and treated against corrosion to MIL and NATO standards for extreme operations.
http://www.coltcanada.com/edged-page.htm