A robust and light alternative to a front glass can be a PMMA coverlens.

Such coverlenses are available in different standard thicknesses and can be printed according to the customer requirements.

Hidden printing can be applied, as can be seen int he following picture. The buttons are not visible in normal mode, only if lighted up.

The edge can be cut to fit the customer housing conditions:

While breakage safety is better for PMMA than for glass, the drawback is the surface hardness. Screatches are more likely than for normal glass.