Well, it would be 2^(7*8) = 72057594037927936 possible intros. Someone/something has to generate, run and evaluate them all. Theoretically it's the "halting problem" all over, to wait for the "final output" of each intro. The 16 byte effect for example takes a while to achieve its final form. So even if it is somehow managed to evaluate 1000 intros per second, we are looking at about 2 million years of time to really test ALL possible 7 byte intros.