I'm not sure I would call the Welsh Tartans 'Hard to come by". They are produced by The Wales Tartan Centre. A phone call or email and the fabric is on its way.

I guess 'costly' is in the eye of the beholder. The price is plainly listed on their website. Take a look and see if you think they are 'costly'.

While the Welsh Tartans are not the same warpwise to weftwise, the Wales Tartan Centre call them Tartans, so that is what I call them.

I will say, that the fabrics that I have received were woven by different weavers and were different. None had a selvedge suitable for kilts so needed to be hemmed.