Somewhat extensive use of captured Brit uniforms was made by Continental forces. Some were used "as is" (i.e. red) and others were re-dyed brown at different stages of the war. I have a smattering of sources on this where you might begin. I would be happy to provide you with a few starting points. It may be a few days before I have time to pull together much of it for you. Below is my e-mail address; contact me after next weekend and we can pursue this further.
To Join the Company of Military Historians click here