If it isn't between 4 - 9 yards long, pleated at the rear with an apron left over right at the front then it isn't really a kilt IMHO. Not too bothered about the material as far as casual kilts are concerned but those skirts with the narrow apron, no!

Did the OP mention 'flat caps'? Potentially a damn fine head dress. Can't stand the silly one with deep backs that look like the wearer has jammed them onto the back of his head but that's a matter of style (or the lack there off) but unfortunately they are not suitable for wear with a kilt and anyone attempting to pervert the course of kilt wearing in that way should be shot, after they have been flogged.

I didn't really get the OPs point about box pleats, they are a conventional pleat, maybe not as popular now as they once were but there is nothing un-trad about them.

Herumph!