A large diycstore do what they call a porch light and I think its brilliant. Size of about two thirds of a balloon. Night time sensor and motion sensor. So only comes on at night when someone moves. Halogen battery operated so we thought batteries would last six years can be permanently fixed to wall or free standing cost about 25 we use it to light way to bathroom.
I got a moonlight light on e bay for mum a couple of years ago, and the other week I got one that is a motion sensor for when you get up in the night but it also charges itself up as a torch that you grab when there is an electricity outage. It was from coopers and I thought it was a great idea.