I've headed down this path on two separate occasions now, and it's been a train wreck both times. Fortunately it got weird soon enough in that we could both pull back without having it ruin the friendship. But there are still those moments where you're sitting across the table talking at dinner or hanging out or whatever, and you're thinking, damn, she looks good tonight; too bad she's going home to -------. Even when I'm in a relationship too. Those moments hurt. If it only lasts a while, you will be able to go back to being friends. If it's serious and goes on a while, you will never be able to get anywhere near what you were before. And I would disagree about it being possible to be friends beforehand; even if you would love to get with her, sometimes it's just such a foreclosed possibility that it never becomes important in your life. Then of course all of the sudden she falls for you, you have a couple weeks of incredible nights and you're happier than you've ever were before, and then she's like "this isn't a good idea." Then you're miserable.
Anyway, go for it dude. If it works out, it will be wonderful, and life's nothing without risks. Look at it this way: if it goes wrong, you're going to have some pain. But if it goes right, it will be wonderful. If it doesn't go at all, you'll be looking back wondering for a long long long time. Hell, what if, instead of saying "ok" when she said it wasn't a good idea, I'd have said "no, I'm fighting for you."? Maybe I wouldn't be drinking boxed wine and posting on letsrun alone in my dormroom on a Thursday night. Maybe I would be posting on letsrun drinking boxed wine on a Thursday night with my best friend snuggled in my arms.