Here's some info on the great kilt:
http://www.albanach.org/kilt.html

Robert,
You are correct that the great kilt would be worn for camoflauge, but that does not meant it would most often be a solid color. We do know that solids were *sometimes* worn in the great kilt -- we have one portrait that shows that c. 1635, but in this case it is solid red.

The camaflauge would have been tartan. In natural tones, the stripes of the tartan design would have served to break up the wearer's outline and camoflauge him, just like a tiger's stripes, or a leapord's spots. So rather than wearing tartan to be identified, people once wore tartan to be hidden!

Jimmy,
Sounds like you are doing something that the military did towards the end of the eighteenth century -- sew in the pleats of the feilidh-mhor to make it easier to put on. I'm doing the same for a client now (or will be, I should say, when the cloth comes in). Nothing new under the sun, I'm afraid!

Matt