I was also looking at tartans on the World Registry and I found some patterns that were interesting.
Dewar's has a tartan.As in Dewar's Scotch.
McEwen's has a tartan.As in McEwen's Export.
Glenlivet has a tartan.As in a fine single malt Glenlivet Scotch.
Just throwing these out there. Cost wise I know these would be expensive but they would also be more unique than most. From the drinking stories of past Castles though they would also be appropriate.