Check out these links. You will find anything from a t-shirt to a button-up shirt without a tie. The kilt is very versatile. If you search the word 'casual' you should come up with some great ideas.

http://www.xmarksthescot.com/forum/f...-attire-46888/

http://www.xmarksthescot.com/forum/f...xamples-85511/