This was linked to earlier, but no one seems to have commented on it.

http://www.semsons.com/pocpowban.html

At 19 bucks it seems to be a better deal than the 1550 and comes with 4 1600ma batteries. Those arent very high capacity, but it is better than nothing. I also have a set of 4 2100ma batteries.

I also bought something similar to this from ebay that I plan to use with it and my laptop Link
I got it for 4 bucks shipped