Elecom is going to release Japan the U3H-S410S 4-port USB 3.0 hub. The hub offers four USB 3.0 SuperSpeed ports that are backward compatible with USB 2.0. It requires external power, however.
The Elecom U3H-S410S measures 86.8mm x 53 mm x 20.5mm. It costs 8000 Yen and comes in white and black.