They partnered with a gourmet candy company called Compartés (pronounced com-PAR-tays). They're available online while supplies last, so it's a limited-time-only thing.
They're called Velveeta Chocolate "TruffVels". Each one is shaped like Velveeta Shells & Cheese pasta, and they're not cheap. A box of five costs 25 BUCKS.
They're filled with the same stuff that comes in boxes of their mac-and-cheese. So they went with a cheese SAUCE, not old-school bricks of Velveeta.
If the cheese isn't a deal-breaker for you, this might be: The shells are WHITE chocolate, not milk chocolate. They used food coloring to make them yellow.
Someone who tried them said they're more cheesy than chocolatey, and the filling really is, quote, "Velveeta in all its glory." They're available at Compartes.com.