It may be low-tech (and decidedly green) but it works, according to this BBC story about donkey powered mobile library sevices.
"If you leave them practising their letters and walk out through the garden gate, you will find another group of children, clustered under a shady tree, absorbed in their books.
Parked alongside them is a brightly painted wooden cart, with sides which fold down to display the shelves of books.
The two donkeys which pull it are resting in another patch of shade.
This is Ethiopia's first Donkey Mobile Library - the brainchild of an expatriate Ethiopian now living in the United States."