The Alps stretch across a good half-dozen countries. And so it comes as no surprise that in some ski resorts a border runs along the summit ridge leading to some après-ski hotspot and duty-free shopping mecca, or a sophisticated luxury destination, or perhaps a more down-to-earth mountain village. Here are nine “borderline” skiing regions ready to test your skills: 1. Matterhorn/Cervino Ski Paradise – Zermatt (Switzerland) and Breuil-Cervinia/Valtournenche(Italy). In the shadow of the iconic peak is the Matterhorn Ski Paradise, which is the highest ski resort in the Alps at nearly 4,000 metres…