Sorry to say, this was already invented. The Plank time
Don't be sorry to say! It should make you happy when you come up with someone that great minds have already thought of, it means your head is in the right place
Thank you, you have made my disappointment more measurable and my day less ruined.
Except observation would be limited by perception, and we definitely can't perceive the speed of light across a planck length. Even the tools we use to measure these things are just measurements, not direct observations.
Sometimes we have those little epiphanies in the shower.. sometimes they come from other places. This is a home for those epiphanies.