I've used solar-powered yard lights at Burning Man for years, and they are not the most robust items I've seen. I don't know about the ones you are considering, but the ones I have don't last more then a few years (out for one week on the playa, so that's a few weeks' use).

Here are photos of one I took apart:
http://civex.smugmug.com/gallery/5099462_pLNsB

Two AA batteries, one LED, a circuit board, and the solar panel. Yours will vary, but it shouldn't be too difficult to dismantle then re-assemble more or less as you wish. I would give it a good testing period before relying on it. It's water proof now, it stays on all night now, etc. Burning Man is a harsh environment, so I may be too hard on them, but I would be interested in seeing how long the units stay working at the claimed specs.