These glass blocks illuminate garden paths, and suggest many other possible applications.
Every so often, I come across a project such as a solar "tree" that makes me go "Of course! What a great idea!" Here's one such, a glowing solar walkway that is net zero all the way. The site includes complete how-to instructions.
If you're looking for a solar power unit that could work for these, try this search for solar christmas lights. Most of these solar packages would work.