HiTechWealth Solar Mobile phone is encouraging.

To know that there’s a commercially available solar-powered mobile phone gives me a lot of inspiration and encouragement that one day in the near future we’ll be able to design UMPCs with infinite standby capability. You could have a panel and electronics that senses light levels and keeps the device in standby (or even turned on) when there’s enough ambient light. When the light levels drop below a threshold for a certain amount of time (based on remaining battery life perhaps), the device would drop into hibernation.

The mobile phone shown here is produced by HiTech Wealth and is available in China for $510. Full news story at SolSie.