Thanks for the pics CMcG, I didn't even think to Google it! Shame on me.

From those and Ron and Jamie's posts, I can easily see that a black/gray/olive would dress up quite nicely, even up to black tie. Now, what about a tan or other color UK? and I agree, the cargo pockets are going to limit how formal you can go. I have a nice brown tweed jacket that would look good with my tan UK, but it has not been converted to a kilt jacket yet. May just throw it on with a nice shirt and see how it looks. I don't really have a need for wearing my UK formally, just interested in seeing what others may have done to get some ideas.