It might be because you're 16 and at this point in their lives, all 16-year-old boys want (not all, but many of them) is an easy girl. You don't sound easy. And that's not a bad thing. Or you could simply not be the right girl for them. Maybe they like you as a friend and that's it.
I'm 18 and have never had a boyfriend. Don't feel bad.
I think you're looking for the wrong guys. You WILL find a boyfriend and you WILL find love (don't worry I'm single too, haha) there is nothing wrong with you, if the guys can't see it, it sucks to be them because they have no idea wht they are missing out on. Good luck finding that GREAT guy, and I hope that you'll stay happy with him for a LONG time (:
I never knew there was a checklist?! I don't think you should be worried who they're going after but who you should be going after. Don't set your expectations too high that what I've learned :) Luck.
Maybe you think you fit this "checklist" but you really don't in their eyes. Guys like what they like and if it's not you then that's not your fault. That's their personal preference. Some guys don't care what a girl looks like because they just want sex or they like her personality, and some guys only care what a girl looks like and won't give a damn if you fit every last trait they want.