Not something you see here often, I suppose.

My entry: Cliq brake lights/taillights.
Currenty $22 to $45. They "learn" your braking and actually act as brake lights.
Multiple mounts, won't break the bank, and can be synchronized to other ones.

Imagine being in a group line of, say, 5, and all your taillights are synchronized, and all are also brake lights.
Visibility.

Others?