Someone posted that he just uses a towel held together by velcro when backpacking.Then he doesn't have to bring any "clothing" but is still covered when necessary.You can get a towel wrap with a pocket and velcro waistband on Amazon. I use these all the time at nudist resorts when I'll need a towel to sit on rather than bringing a full sized towel around with me. Gives similar coverage as a kilt and is very quick to put on/take off. I could see using these when hiking.
And if you are trying to minimize what you take, you can dry off with it too!
I guess what I have is called a bath wrap not a towel wrap. They still make a usable kilt if you dont care about fashion and do double as a towel. I have worn mine on a hike recently, but it was at the nudist resort due to an unseasonably cold Fourth of July weekend not as a quick cover on a public trail.