I think you should have clothing of different cultures, like Spanish dresses, hula skirts, japanese kimonos, bharatnatyam (sp?) outfits (this is an indian dance in case you have no idea what i'm talking about) and such. I could help out with research on clothing if you need, I might go into design when I am older
I would love to see flowers for girls, to put in their hair. Some of the latest trends, like loose camo pants for girls. Denim skirts, belts, raglans, and some other cool stuff (leggings!). Most girls would probably love the idea of the new treads. As for guys, hoodies, some camo too, jeans, sneakers, jerseys etc.
If you ever need ideas or design help I'd be more than happy to help