The issue here is that the KY tartan is not one that is stock supported by any woolen mill. This means that you can't just order a single kilt in this tartan, like you could Campbell or MacDonald. This would explain why the pipe band orders their kilts 8 at a time.

However, many kilt makers (myself included) don't mind dealing with special order tartans in small runs for a single kilt. This, of course, is more expensive per yard than if you ordered in larger quantities. But it is doable.

And there are ways of keeping the cost down. One of them is to order a kilt with less yardage. For instance, the four yard box pleated kilts I make only take half the yardage of a typical modern kilt. I charge $480 for a kilt in a special run tartan. This is still less expensive than a typical eight yard kilt in a standard tartan. It's a way of getting an unusual tartan at a price point that is typical of most standard kilt.