Geoff beat me to it. In the Corps, one would never wear a kilt because it is not regulation uniform dress. In fact, you'd probably get written up for wearing it with uniform articles of clothing. The Corps is very particular about unifrom regs, and that's one reason Marines always look good.

Having said that, I have seen a local fellow who had a dress blue blouse cut down to kilt length and modified with a sporran cut away that looked really good. If you remove the military buttons and replace with just about any brass button (to keep it legal), and not wear USMC badges, etc,. you'd be fine. But only as civilian attire, not as military uniform dress.