Andriod = a mobile device operating system from Google and just getting into the main stream and shows promise. But it remains to be seen just how long it will hold the attention of 3rd party developers. And many developers these days seem to have the attention span of a gnat on crack.
If your mom is ok with it and there are funds in the budget then consider the iPad. The plain Wifi version should be fine. Though it might be overly complicated for her to absorb the gesture based touch interface. It's not an awful device, in fact Harry, who has used a TON of readers, really likes his. I have seen them and they are nice looking. Trade-off's exist of course.
Otherwise there really aren't any backlit readers out there yet...Pocketbook did announce a Pocketbook IQ will be out in short order. It's shown in the first post for this thread. I don't know if it will run any version of the Kindle software...if it runs Android then it should...
I will add any tablet/slate style device that is not a dedicated reader could be intimidating for older people who just want to read. I would tend to agree that the K3 with the genuine Amazon cover with integrated light is an option BUT I would also say that needing to use the reader inside the cover (the light is powered via the hooks which hold the reader in the cover) defeats the whole idea of the light and easy to handle device.
BTW, I agree with your mom...clip-on lights are silly and I have yet to find a single one that is not so annoying as to ruin the whole idea of relaxing by reading.
Wish I had more devices for your but nothing that was promised at the beginning of the year has seen the light of day. World economy and what not are, in part, a reason as companies need funding and investors who right now are happier to invest in less risky options.