Sharp have been demonstrating a solar-powered HDTV at CEATEC 2008, capable of operating solely from the power generated from sunlight. The 52-inch set uses an LED backlight and other energy-efficiency technology so as to reduce it's power requirements to just 220kWh; coincidentally, that's the same amount as the solar panel generates.
Of course, in its demonstration setup this wouldn't be much use - unless you watch TV outdoors, or don't have a roof - but I'm imagining that Sharp intend for the solar panel to go onto the roof rather than at the base of the set. It's actually a demonstration of both the company's high-power solar panels and their LED-backlight efficient TVs.
No word on when we could actually order either the HDTV or the solar panels, nor what sort of price they'd cost. It'll be interesting to see how other manufacturers address the green tech balance as sustainability and the environment become even hotter topics.