The complications:

1) I anticipate that when I finally pleat the kilt, I may have a hard time hiding the joins (as Alan H says "...they could buy two yards of the 60-inch wide fabric, cut it in half and sew the halves together, end to end....Well, I'm going to tell you NOT to do that.
Why? Because it's complicated. You can't predict ahead of time where that seam is going to fall, and it's complicated to design the kilt so that the seam is hidden inside the pleat").

2) There is the issue of the knap of corduroy being "one way" as the clerk at the fabric store (and O'Neill-thank you!) pointed out. So, if you join it wrong, it looks "upside down" on part of the kilt.

It is necessary to join fabric when using corduroy, because the lines of the corduroy run the length, not the width of the fabric (if they ran the width, I could follow Alan H's directions to the letter). Unless you can get fabric that is about 140 inches wide, you have to cut sections and join them to get enough to make a kilt. Or, you could make a kilt with the cords running horizontally...which would look very strange, in my opinion.

So, next is how I joined the fabric...