I am Scottish but I am not aware of my forefathers ever having worn kilts! My concept of what is traditional in Highland Attire simply developed through using Xmarks... otherwise I'd be clueless about everything.

I would say many developed trends within Highland attire can be considered classic, though not traditional. Such as a large number of kilt-wearers in the early 20th Century wore large horse and goat hair sporrans with shiny cantles for daywear. I would consider this more classic than traditional, though, I feel it evolved out of tradition.

I feel a lot of modern pleating styles - including that of Scottish regiments is very much classic, though, some are not traditional. They have developed through the need for something a little more practical; just as many concepts of kilts and accessories have.