Well, I finally found a copy or Major C. R. Wheat’s report of the actions of the 1st Special Louisiana Battalion at Bull Run. It was hiding in plain sight in the Supplement to the ORs, and was sent to me by friend of Bull Runnings Jonathan Soffe.
As discussed in this post, the report of Wheat’s commander N. G. Evans claims that the Battalion captured a regimental color during the fight. Wheat’s report unfortunately does not mention any captured banner, however he does make mention of the capture of some artillery pieces. Is it possible that the captured colors in question were actually those of a battery?
Also, I have more on the Wheat ambrotype recently “discovered” by Mike Musick and discussed here and here. Mike sent me a big packet of info, which I mentioned here. I haven’t forgotten – I just haven’t had time to get to it yet.