I use my Cybook with a Mighty Bright XtraFlex 2 LED Light clipped to the cover and it works great. There is enough light to cover the whole screen and very little 'extra' light so hubby can sleep while I read. I'm sure this option will work well with the BeBook as well.
This is the light I have, I bought it a local bookstore:
http://www.mightybright.com/Book_Lig...uctDetail.html