I was on the phone with The Scottish Weaver (member here, but not sponsor, as far as I know) and he mentioned that they have some tartan "laying around" that he would like to get rid of (but are NOT on the clearance page of his site, for a specfic reason).
He has some Kelly of Sleat worsted wool. He has 2 types, both th 14 oz twill.
Kelly of Sleat Hunting/Green for just under $30/yard.
Kelly of Sleat red for $35/yard.

It is of the same weight and from the same mill as our X Marks tartan fabric, so it -should- look and feel the same (material-wise, not color-wise. He is also doing a run of "custom" Carolina tartan in 10/11 oz worsted twill weave for $39.95/yard. It is a bit on the light side for a kilt, but not too bad. My -MIGHT- get some for the "cut-and-sew" tartan hose, I REALLY want. He will have about 20/yards for sale when he gets it.
(No connection, nor the intent of my call, just a bit of info I was told and thought I could pass on to interested parties.)