I'm thinking Raleigh/Durham/Chapel Hill. Lots of good universities there. I've never been but I have heard good things.
Three good universities within <30 minutes drive of each other, each in a city of a different size and feel at each anchor point, with a business/job center smack dab in the middle in Research Triangle Park, which has plenty of room to grow. And still a great COL at the moment. I'd agree that we could/will be the next Austin (but I live here so of course my perspective is biased) as long as we don't self-sabotage, which is a real possibility. For example: Duke University just effectively killed the planned Light-Rail between Durham and Chapel Hill for some reason.
Houston. We already have a large international tech base, built-out infrastructure, and a (slowly) developing mass-transit plan. Added benefit is that we're just 163 miles away - short move for folks that burn out on the Austin eXperience.