The edge beyond Geranimals
The web site (LIttleMissMatched) is totally lame, but the idea goes straight to the edge.
Mismatched socks for 11 year old girls. Hundreds of varieties. Four categories so you don't clash. Only sold in odd lots.
Think about how easy this was to do, and how remarkable it is. Think about how many sock marketers thought of this and then got scared and didn't. Realize how turning socks into a remarkable collectible is both obvious and satisfying and likely to succeed.
I wish they came in my size.