California company V-Dimension offers laptop and gera bags that use sunlight or room light to charge portable devices such as cell phones, iPods and PDAs.

Some of the information on the company website is more philosophical than practical (as in "Somewhere between the horizon of our dream and the sunrise of our vision lies the future of imaginative technology, and the perpetual improvement of our quality of life"), but there is a simple how it works illustration on the site as well (copied after the jump).

They offer three different models, the Corporate Travel Case, the HELIUS Backpack, and the Optical Messenger Bag (pictured), all priced at $129.95. Made of nylon and able to accommodate notebook computers up to 15.4 inches, each bag comes with adapters for the iPod/iPhone, mini-USB, Samsung, LG, Nokia, and Motorola. A full charge takes two hours, and the storage capacity is up to two full charges.

Question: Why are these kinds of backpacks almost always offered only in black? How about colors that are little more sunny?