I can certainly feel for you guys having been in the same boat just a couple days ago. As soon as I stopped looking at email and just accepted that they weren't going to ask me to interview, I got the request. That's probably not much consolation though.
I actually live in Charlottesville and part of me thought
Well, they're just making me wait because they know I don't have to make travel arrangements to get to campus. To a certain extent, international candidates are in a similar position. ADCOM can wait toward the end and send out a skype interview request knowing that you're not going to travel to campus. At least, that's how I would rationalize it to myself.
I went through a period of enormous frustration where I got really upset. I kept thinking,
If they'd given me more than one essay and two short response prompts I could have at least shown off my Darden-specific knowledge. Are they just turning this into a stats contest? This might be the only time in life I've asked for a chance to write more