[thfuran]

Isn't it exactly the point? If, provided sufficient cooling, you could double the clock speed without running into clock skew or other timing issues, then timing issues shouldn't be a problem if you want to scale things up physically by 50% without touching the clocks. I don't think you'd have to lower clocks by 90% to increase size of most designs tenfold. Or rather, that the reason you'd have to if you did wouldn't be due to signal propagation time.