Had to come back to this thread.
Last night I read a chapter of
The invention of tradition, edited by Hobsbawm & Ranger.
In it, Hugh Trevor Roper completely debunks the notion of the kilt being a traditional Scots garment.
The truth is that only Highlanders (seen by Scottish lowlanders as as a right bunch of Irish ruffians) wore the plaid, which was a blanket (not even tartan either, usually brownish stripes or flecks to blend into the heather) wrapped around the torso and coming round the body to end as a short skirt exposing the thighs and pretty much anything else in a half-decent breeze.
Lowlanders wore breeks and stockings and a coat or jacket.
Anyway, a Lancastrian industrialist, Rawlinson, seeking fuel for his iron furnaces, went to the Highlands and recruited men to fell trees and tend the furnaces.
Their garb, whilst suitable for living rough in the heather, was pretty useless for the sort of work that Rawlinson hired them for, so he worked with a tailor to adapt the plaid into a filie beg (philibeg) ... or kilt as we now call it.
To set the example, Rawlinson was the first to wear it.
So, not really Scottish at all.
Hugh Trevor Roper goes on, to further debunk the idea of tartans as a traditional signifier of clan.
As Scottish history (especially Highland history) was re-written (faked by two guys names McPherson) to depict the Irish as having aped Scottish Highland culture instead of the truthful other way round, the kilt became popular but fancy tartan patterns were the preserve of those who could afford them and there are pictures of clan chieftain families where many tartans are worn, befitting fashion rather than anything else. Their lessers wore simple brown philibegs.