Two things that might be of interest!
1. The Norhtec Gecko Edubook, which is essentially a really fast 586 or 686 which will run Linux, and can do so using AA batteries. It will also run Windows XP, but as you may know, I do not recommend Windows XP for networked computers. (I also have an IBM Z50 with an AA battery pack, but that's a lot less modern, and is basically a Windows CE version of the eMate, sort of.)
2. There's also the Sol laptop, which is more modern, using anything from an Intel Atom to one of the new Core M chips. It's also more expensive, but you basically buy it, take it out of the box, put it in a window and then start running linux or windows 7/8, so it's up to you to decide if you like that sort of plug-and-play-ness. Engadget did a hands-on a few months ago, too.
For me, the question is, are you just living off the grid and want "a computer" or are you looking to have all the hardware contained within a reasonably portable "laptop"? The newest small $200 Windows computers all use Micro USB charging and most of them get over eight hours of battery on their own, so you could just get a solar charger that uses Micro USB.
If you're willing to make an installation with batteries and all that, it's more about how much space you're wiling to take up and how low-power a regular computer you can find. Even then, using some car batteries to charge one of the modern tiny Bay Trail laptops (or even, say, a bigger laptop from System76 or a desktop) would be a really neat project, especially if you're in a sunny place.
1. The Norhtec Gecko Edubook, which is essentially a really fast 586 or 686 which will run Linux, and can do so using AA batteries. It will also run Windows XP, but as you may know, I do not recommend Windows XP for networked computers. (I also have an IBM Z50 with an AA battery pack, but that's a lot less modern, and is basically a Windows CE version of the eMate, sort of.)
2. There's also the Sol laptop, which is more modern, using anything from an Intel Atom to one of the new Core M chips. It's also more expensive, but you basically buy it, take it out of the box, put it in a window and then start running linux or windows 7/8, so it's up to you to decide if you like that sort of plug-and-play-ness. Engadget did a hands-on a few months ago, too.
For me, the question is, are you just living off the grid and want "a computer" or are you looking to have all the hardware contained within a reasonably portable "laptop"? The newest small $200 Windows computers all use Micro USB charging and most of them get over eight hours of battery on their own, so you could just get a solar charger that uses Micro USB.
If you're willing to make an installation with batteries and all that, it's more about how much space you're wiling to take up and how low-power a regular computer you can find. Even then, using some car batteries to charge one of the modern tiny Bay Trail laptops (or even, say, a bigger laptop from System76 or a desktop) would be a really neat project, especially if you're in a sunny place.