I absolutely love the Sony cover with light as well and use it most of the time (mine is blue though, I'm not a pink person at all and wouldn't use a pink one no matter how bad I wanted the lighted cover). However, now that it's hot weather, too hot for even a vest with lots of pockets, I'm forced to use a small purse and sadly it's too narrow for the lighted cover. So I now use this Verso light that I love until it's cold weather again and I get back to my big pockets. This light is small so it also fits in my tiny purse when I think I'll be out reading when it's dark, and I just slip it on when I need it. It's actually a very good light also, lights up the screen on my 350 very nicely and pretty evenly, no glare spots at all. And it's rechargable, no batteries to deal with. It lasts just about as long as the Sony cover between recharges.
http://www.lightwedge.com/Shop/E-reader/Verso-Arc-Light