Not only does Livity make their entire line from recycled materials and organics, but everything is produced in equitable trade. These trunks are made from recycled plastic and hemp. They are quick-drying, and feature some cool patters and prints.
Loomstate's Baja Board Short in organic cotton are less bold, and feature a leaf-inspired print.
Patagonia also has a handsome khaki, or khaki check board short in organic cotton.
If you care about the oceans, there are some great resources out there for ethical surfers, like EcoBusinessLinks page on surf companies. Country Feeling Surfboards uses soy-based and sugar-based foams; deck inlays made from hemp, organic cotton, bamboo, and resin that is catalyzed by the sun. The best surf accessories, like hemp boardbags can be found at Wave Tribe. If you have an old board to recycle, send it to ReSurf! I also highly recommend joining the efforts of Sea Shepherd.