A little late I know, but I was just reading about the reworked
Black Island, and thought the following might be useful, if anyone were thinking of buying or making a Tintin-appropriate kilt...
The issue of
Tintin magazine dated 1st June 1965 featured a special cover by Hergé, which advertised the fact that - starting inside - was the "revised, corrected, rejuvenated and entirely re-drawn" version of
The Black Island.
Against a tartan background it shows Tintin and Snowy surrounded by places and characters from the story. Tintin is in his Scottish outfit from the adventure, and for the first time his kilt has been rendered in more detail that the simplified red-with-green-striping with which we are more familiar; in fact, an attempt has been made to show that it is the same tartan as the background of the page.
As such, Royal Stewart (the tartan used) isn't a clan tartan,
per se, but that of the monarch; it is generally held that any subject could therefore wear it, but that permission should be sought by organizations which which wish to use or incorporate it into uniforms etc.
However, it has been so widely reproduced and used that it is now classified as a "Universal" tartan, and can be worn by anyone wishing to wear a tartan and who isn't entitled to a family tartan.
Tintin obviously isn't (at least in the original books) a British subject, but as he gets his kilt in extreme circumstances, I am sure Her Majesty wouldn't object anyway, but the universality of it now makes it a good choice for a non-Scot.
By the by, if you are looking for a simpler red and green tartan you might want to consider the
Stuart of Atholl or the
Ancient Cameron tartans - neither is precisely as drawn in the book, but the colouring is close, and the look might be achieved.