I guess Webkinz gave up on make the kilt Skirt a semi-exclusive item because it is in the W Store now, along with a Mod Jacket.

The Mod Jacket is an old style jacket that came in to popular culture around the early 60s. The Mod Squad, the Who - think Austin Powers. But this only looks sort of like those jackets so who knows what the deal is there, perhaps this item is just inspired by the old mod clothing styles.