I seem to recall that named tartans were not supposed to be offered for sale on eBay, however...

For the next six days a seller has four offerings of 4 meters double-width of each tartan listed below, starting at around $50 (one has already gone up to nearly $100 for four meters - still a great price.)

Forbes - item# 150068054341
Leslie - item# 150068054879
Rose Hunting - item# 150068055481
MacKenzie/Seaforth - item# 150068055949

Probably have to watch out for the overseas postage, and who knows what Customs might do, but it may turn out cheaper than a direct buy from a mill or a US importer.