I just found this by chance, amazing! A US Army report on four panthers found during the Battle of the Bulge, that had been cleverly and accurately disguised as US Army M10 tank destroyers.
From the Army report;
"Investigation of four German Panther tanks knocked out in the Malmedy area in the December breakthrough in Belgium revealed that the tanks were carefully and cleverly disguised as U.S. M10 gun motor carriages.
After inspecting the tanks and realizing the amount of time, work, and materials involved in order to imitate the appearance of the M10, Ordnance intelligence investigators expressed the opinion that these disguised tanks, used in the proper tactical situation and at the proper time, would have caused considerable damage."