Box pleated kilts are a traditional style that dated back to the end of the eighteenth century. The original tailored kilt was box pleated and made of about 4 yards of cloth, as compared to the knife (side) pleated, 8 yard kilt that is typical today.

I make traditional four yard box pleated kilts. There are some good illustrations showing the difference between these kilts and the modern knife pleated kilts here:
http://kilts.albanach.org/details.html

Lady Chrystel of France (and a member of this forum) makes kilts in what she describes as a "double box pleated" style. As far as I know she is the innovator of this style of pleating in a kilt. As the name implies, each pleat is folded over twice (or doubled) to give the pleat somewhat of an "accordian" look. It uses more cloth and will give more bulk to the back of the kilt.

Here is an illustration from her web site showing the differences in pleating styles. Pay attention to the middle two.


Her web site is:
http://pagesperso-orange.fr/lady.chrystel/kilts.html

Both her web site and mine have picture galleries of some of the kilts we have made, so spend some time browsing and you'll get a sense of the two different styles.