I designed two custom icon sets for AppArtEment that you can use for your iphone and android based smartphones. The first one is about a chubby bunny and the second one is a blissful scene from a koi pond. There are enough custom icons that you can assign for multiple apps.
There are also a handful artsy custom icon sets made by Japan based artists and musicians.
Download the app from here (the app is in Japanese, but it is easy enough to navigate):