As it is, this gravity-based application method requires a screen, separate from the wall, that can be positioned horizontally to sprinkle on the glass. I'm not at all convinced that my method for building the screen (nor for attaching it to the wall) is the best one. Improve it!
The final surface--glass beads embedded in latex house paint--is surprisingly robust. I was at first concerned that flexion of the screen would cause the beads to flake off. Fortunately, the latex paint retains plenty of flexibility, at least over the few weeks my prototypes have existed. I almost think you could go so far as applying it to a thin surface that actually rolls up.
Another pleasant surprise was that, at viewing distances, the surface treatment is remarkably tolerant of small imperfections, and does not require a very smooth texture. I believe it could even be applied directly to a textured wall, and the next step is to figure out a convenient process for doing so, thus eliminating the need for a separate screen altogether. Stay tuned!