Yup, that's the speed of light, all right. I agree, I bet there's a connection. We idealists are always saying that consciousness is what the universe is made out of, right? (I think of the Kybalion, here: "The All is Mind; the Universe is Mental.") It's certainly conceivable that light is the mode by which consciousness appears in matter.

Plotinus also likened the One to light (just as the Intellect is like the Sun, and souls are like the Moon, and bodies are like the Earth). The Intellect is what shines the One to us below...