As something of a completist, and also because I feel the flags are actually rather attractive, I have decided to do the rest of the ex-Saxon regiments "borrowed" only temporarily by Frederick. Here is IR50, formerly Saxon Regiment Rochow Fusiliers.
From October 15th 1756 to July 30th 1757 it was commanded by Major-General L. F. L. von Wietersheim.
IR 50 was made the garrison of Halle in October 1756. In 1757 it accompanied Frederick's army for the invasion of Bohemia. On 30th July 1757 the regiment was disbanded after a large number of desertions and the remaining men were drafted into Prussian infantry regiments 7, 29, 35, 36 and 41.
And this was the uniform in 1756:
