Not to unnecessarily bump this, but I ran across this site a few days ago when doing a bit of tartan searching.

http://www.weddslist.com/cgi-bin/tar...rce=sts#result

Gives the thread counts in the warp and the weft (if the weft is different). Also generates a computer image of what it looks like (vaguely, as best as the poor thing can do)

Can give thread counts for straight and diagional (bias) weaves.

Might be helpful. I'm not a weaver, so I can't say for sure.