There has been some interest there about the Northumberland tartan (also called the Shepherd's Check). This is a very simply black and white tartan that can be expressed in the basic formula K = W. In other words, it doesn't really matter what the thread count is, so long as the black and white threads are equal.
The same design in different colors is used as the Rob Roy tartan (K = R), the Moncrieff tartan (R = G) (this also is an old MacLachlan tartan, by the way), the Robin Hood tartan (K = G) and some other variants.
It is an extremely traditional design. The oldest tartan found to date in Scotland, called the Falkirk tartan (being discovered in Falkirk) is a simply check of light and dark undyed wool.
The tartan came to be associated with Northumberland, in northern England, because it was adopted as the official dress of the Duke of Northumberland's piper in 1760. From the Northumberland Tartan Company web site:
It is not widely known that the county of Northumberland has an official tartan and moreover that this tartan is held by many to be one of the oldest check patterns, predating the more colourful Highland tartans which followed it. The Northumberland Tartan, variously known as the Border or Shepherd Plaid, is also closely linked to the Percy family, forming the official dress of the Duke of Northumberland's piper.
You can read more history on their site. You can purchase this tartan through the Northumberland Tartan Company, of course, but also through any regular tartan retailer under the name "Shepherd tartan." It's the same material.
I've always liked this tartan. Probably partly because my own surname of Newsome is English (though not from Northumberland that I know of), and partly because of the extreme simplicity of the design.
What I do not like about the tartan, and the reason that I have never owned a kilt in it, is because it is always produced with such an incredibly small setting. Even in heavy weight kilt cloth, the thread count is miniscule. Here is a picture of a gentleman wearing a kilt in this tartan. (This was taken a couple of years ago at the Stone Mountain Highland Games in Georgia).
The kilt does not look bad, mind you. The small pattern is simply not to my taste, and not to the taste of a lot of men I talk to about this. Compare this to the size sett you typically see the Rob Roy tartan, or the Moncrieff tartan woven in. I've seen those tartans woven with anything from 1" to 4" squares. I've always thought that the Northumberland/Shepherd tartan would look much more striking (and much more masculine) in a larger setting.
If I were ever to own a kilt in this tartan, I would have the cloth woven for me in a large pattern, perhaps with 2.5" squares or so. It would cost a bit more than using the cloth that is standardly available, but I think it would be worth it.
To give some idea of what that would look like, here is a picture of a kilt I made for a client in the Moncrieff tartan (red and green). I edited the photo to be black and white and played with the contrast and brightness to achieve something like what the Northumberland tartan would look like on a larger scale. I think I might even go a bit larger than what is in the photo, but this gives you some idea.
So how about it woolen mills? When your current stock of heavy weight Shepherd check runs out, why not try weaving it up with a larger setting. I'm willing to be it will increase your sales of kilts and cloth in this tartan. In the mean time, if anyone wants a kilt like this and doesn't want to wait for the tartan industry to begin to produce it in a larger pattern, let me know and I'll be glad to order up a small batch for you (and maybe enough for a kilt for myself while I am at it!)