Grr, can't seem to fin the pics I wanted...
Well, see the hat Taiji has on in this pic
It's (almost) the same hide has in the vid (actually I wanted to post a pic where both of them have the hats on but couldn't find it).
So, I believe they went shopping (or, to be realistic, drinking
) and, well, something must've struck them to do the partnerlook thing (what do I know, I've never been drunk :twisted: ).
So Taiji kind of stuck with the cowboy thing (at the beginning, it was just the hat and his old 'lady Taiji' clothes, then the complete outfit) and hide wasn't really that much into it (tho, later...).
All I'm trying to say is: It's all hide's fault!