Omfg Yuuki is so cute! This character has so much loli potential that just isn't exploited - even in doujin.

Come on, she's in love with her much older than her brother and has been messing around with him since she was four in the canon manga, and happens to be a super moe vampire jb chick who blushes whenever Kaname touches her but has no problem pinning him to a bed and sinking her fangs into his neck.

For super cute fanart of Yuuki you can check out Sagakure.

I'd post something of hers here but she always throws an epic fit whenever anyone posts her art anywhere and puts a TL;DR warning in when she translates VK for onemanga about not 'stealing' manga scans.

Her dA:
http://sagakure.deviantart.com/gallery/#Vampire-Knight-fanarts

Her LJ:
http://sagakure.livejournal.com