We decided to use the Pixapro led100 for key.http://www.essentialphoto.co.uk/product/pixapro-led-100d-studio-light/
It is very powerful, albeit not on battery power. But for our needs we decided to have the key light on mains power, all the other lights (fill, hair, background etc.) are battery powered. For us this was the best compromise between light output vs. ease of set up. The light is so powerful, it gives you a lot of flexibility; you can even shoot with a window in the background. From a portability point of view it is not that bad either; more bulky than a 1x1, but no that much. From the same company you can also get low cost - good quality soft boxes.