Minimum Solar Light
Combine one of the new powerful LED lights powered by a couple of CR2032 button batteries like the Energizer Trim Flex LED with a solar panel from a novelty solar hat fan or one of the PV chips from a solar education kit, connect them together, possibly with a IN4003 blocking diode between the solar panel and the batteries to prevent electrical discharge through the panel at night (correct me if I'm wrong), and you have an effective solar rechargeable light suitable for reading.
There is a button battery solar charger which works fairly well. There is also the Micro Solar LED which I have not tried yet. You can also buy rechargeable button batteries and AC chargers.
I'd like to see solar light as available and affordable as a disposable cigarette lighter anywhere and everywhere around the world. Right now the price for this level of solar light is between $20 and $10. Commodity production and pricing should bring that down to $5 to $1.
Interviews and Site Visits
Crossposted to http://gmoke.dailykos.com
Solar IS Civil Defense