Horace raised this topic on another thread.  I thought it worth picking up.  The entire Harris tweed business is a complete puzzle to me.  I must have seen several hundred examples during the past twenty years, of varying quality, and including some I found wholly dubious - with an interior zipper.  I didn't examine every single one but a 'vintage' seller opened up a huge box last year and invited me to rummage through them.  I recall Brooks and Banks.  Didn't buy anything.  Nothing was in my then porky size.  All darted, I'd say. 
Now: is there some Far Eastern connection?  Nothing would surprise me.
I tried switching to Donegal tweed.