I have been using the Energizer Reading Light and was very happy with it. Recently, I just got the M Edge Jacket for PRS505.
Unfortunately they dun seemed to work well with each other as the Energizer light is too long for the jacket. So I have to actually bend the light's body in order to keep the light in the spine of the jacket when not in use ! But I managed to get by
Some photos
here
Looking forward to an actual version of M Edge light for Sony PRS505