Go to any commercial glass supply company, such as ones that sell glass for residences, businesses, etc. You should get tempered safety glass that is at least 1/4" thick, and if your gear is heavy, then I'd suggest 3/8" thick (which may have to be special ordered). Have the company cut pieces to the sizes you require, and have them bevel the edges to eliminate sharp edges.
One last "tweak" you might want to consider: if the glass is going to be hidden underneath a component, but may be subject to picking up and passing on vibrations, then get a sheet of restrained-layer damping material, such as used in cars for car audio, and apply it to the glass. I used a material called DexDamp, which I got from a marine supply company, but car audio installers also a similar material.
Last, if the glass will be supporting a vibration-sensitive component, then put isolation devices such as Vibrapods or Sorbothane pods under the glass, either at each corner, or in a triangular pattern.
One last "tweak" you might want to consider: if the glass is going to be hidden underneath a component, but may be subject to picking up and passing on vibrations, then get a sheet of restrained-layer damping material, such as used in cars for car audio, and apply it to the glass. I used a material called DexDamp, which I got from a marine supply company, but car audio installers also a similar material.
Last, if the glass will be supporting a vibration-sensitive component, then put isolation devices such as Vibrapods or Sorbothane pods under the glass, either at each corner, or in a triangular pattern.