Fun idea, but I can see a potential problem when the time comes to mow. I think the glowing rocks need to be contained somehow. Or maybe use larger painted rocks to line a walkway and just plan to use an edger for trimming the grass.
Looking for an out-of-the-ordinary water feature? If you don't have a slope for a waterfall and a fountain won't do, consider a 'rain shower' structure like this. This contemporary design would work well in a high-tech or zen garden.