I would like to think I'm a social INT. In fact, I probably appear to be more extroverted to my more introverted friends and have been mistaken as such. But, when around those who are truly extroverted, like one of my friends in college who likes to try to introduce me to the wonders of college parties (ugh...), or my brother who loves to be around people ALL THE TIME, you can most definitely tell I am introverted.
I find that if I spend a weekend around just my friends, I probably want to spend the rest of the week alone until the next weekend. Also, I tend to speak less if there is a large group of people. I think this is usually because of a combination of not being interested on wherever the conversation is going, processing what each person says (and possibly re-evaluating my own opinion) before adding in my two cents, and just being down right shy.
So, based on my own experiences, I suppose an INT can definitely be social, so long as they have a period of downtime to recharge and if they spend their social time around a small group people who share the same basic interests.