My friend and I cosplayed as Elizabeth and Margaret from Persona this year and we used yellow contact lenses called "Solar Eclipse". They look really good and are very vibrant. YouKnowIt.com
sell those lenses, among other sellers.
Here's a photo of us in cosplay wearing those lenses: http://www.cosplay.com/photo/3263635/
I also wrote a review of the lenses here: http://www.teamblasecosplay.com/revi...eclipse-review
I also really want to try the Princess Pinky Twilight brown that were suggested by the others above. I'm just a bit worried about the large pupil hole, but maybe it's not a valid concern, I guess I have to try them to know.