I gotta agree with those suggesting practical solutions.
As far as I'm concerned, this is not a lost situation. If you actually make a move on her you will go up 10 notches on her "is this guy a man?" rating and if she's feeling horny at the time she might give in to a kiss. She's already comfortable enough around you.
So what you do is stay friends, but over the span of a couple of weeks, show less and less interest by calling less or whatever. At the end of that span, you invite her over for a night in (it would be ideal if she invites you and you just accept). Be a bit colder than usual. A bit ****y. A bit funny. Touch her more than you normally would do while teasing her and then move in for a kiss once you feel the moment is right. Preferably right after you feel some sexual tension (which will usually follow after you touch her and make a joke about her).
If she lets you kiss her, you've just proven that you're a man. Come back and tell us exactly what happened and we'll give you more advice.
If she doesn't let you kiss her, give her a nonchalant "OK", freeze her out, say you better get going and leave.
Forget about her unless she calls and invites you again WITHOUT mentioning the events. This might be a sign that she's gonna let you have your way the second time around.
If she doesn't invite you, or she does mention the event in a negative way, or says she just wants to be friends. FORGET ABOUT HER FOR GOOD.
Just my opinion.