So do you find odd tartans?

[ForresterModern]

Or you could order a machine sewn 16 oz from Tartanweb for around $431US plus S/H and a wait of several months for the custom weave tartan. Or the same form Scottishkilts.net for $406 plus s/h and the same wait.

[O'Callaghan]

As a rule, registered tartans have been woven. It's a condition of registration. OTOH, the sample of a few yards that was woven for this purpose may be all that was ever made in some cases.

Many registered tartans can only be had as a 'special weave', i.e. woven to order, and this can get expensive. There are several in this category that I would like, but probably won't get, e.g. Callaghan (Irish clan), St. George (England) or Arsenal FC (soccer team). I believe some kilts may have been made and sold in the Arsenal tartan through the club, but I don't think that there are any left, or any plans to make more.

OTOH, Scotweb sells kilts in some relatively obscure tartans that I'm interested in, such as Munster (Irish kingdom, ruled by Callaghan of Cashel from 915-953) or Maryland (US state). However, they want approx. $300 for the former and $450 for the latter, just for a 4yd casual kilt, and I believe about twice as much for an 8yd kilt. They may well be the sort of people who would carry the Seabees tartan, but it would be in that ballpark pricewise if they do, and their prices for different tartans vary considerably.

Some of the Pakistani kiltmakers will make kilts in any tartan for rock bottom prices, but you may have to buy a dozen! (That may still be cheaper, and you could re-sell the other 11!).