On the 4th floor of the new American Indian Museum in DC there is an exhibit detailing the effects of weapons technology (first swords, then firearms). The final section of the display has a Garand, G3, AKMS, M16A1 (missing ejection port door), and....a Colt ACR!
For those of you who don't know, the Colt ACR was an experiemental rifle for the Army. It had a very Crane-like stock on a 7-pos tube, flattop upper, ambi safety, thicker grip, and forend with different front sight, heavier barrel, compensator, and a sort of instinctive trap-gun like rail atop the handguard. Unit at the Smithsonian (Indian Museum) sported an ELCAN optic.
Sorry I didn't think to take pictures; I think my wife was carrying the camera anyway. So for those interested, you can view it to your hearts content, if only the starboard side and at a 6" distance, behind plexiglas...BT