We could be guilty of overthinking this: is this a real problem, or one of perception? Probably the latter. I'm always in favor of as few rules as possible, and I know for a fact that good shooting is the most important factor in a BC.
Seems to me, if you set a limit on the BC (2 or 3 times) that takes care of the percieved problem right there. No need to limit uniforms. If i'm no longer eligible for a BC, then none of my uniforms are. Best I can do is win my shooting class, which is all I want to do anyway. If I sell my uniforms later, then someone else has a chance to win with them. THey've still got to shoot, and shoot well.
Maybe (Thinking out loud here, just thinkin'. JUST thinkin' dangit!) Instead of Judging uniforms, we establish a standard that must be met in order to be eligible for a BC. Meet the Standard, and you're eligible. Call it a uniform inspection. You declare you wish to be considered for the BC. At this point you will be inspected in accordance with the field regulations of your chosen service. Pass inspection, and your entered into the list as BC eligible. At this point, the BC then is selected from the those eligible folks who accumulate the most points in their skirmish class, and in their long range element, just as now. And just as now, if there are no BC eligible persons who finish top 3 in both elements, then there is no BC.
We still have a seperate judging for Dress Uniforms, or perhaps reserve Dress uniforms for the Dining in we're contemplating?
Got my foxhole dug, have at it!