Where is the big mystery here? You could apply "ecoboost" techniques to a 460, it would be killer. Add small turbos, DOHC and 4 valves per cylinder with valve timing and direct injection and it will clearly make tons of power. These technologies have allowed engines to make power over a much wider rpm range with a lower fuel consumption than before, and would work on any displacement or cylinder configuration - it's simply a matter of deciding how much power is needed.
Of course if the displacement is big enough you can make tones of power NA too, it's just less efficient in terms of power produced per fuel used.
Torque vs rpm is an irrelevant discussion - they are two ways of presenting the same data. I can change a plot of torque vs rpm to one of hp vs rpm with no additional info, they are the same info. In physics, power is what does work. The problem is that people try to assign meaning to the torque figure that it doesn't have and just confuse themselves. The rpm the engine makes power is irrelevant, rather it's the shape of the power curve that matters. Just use gears to move it up or down in rpm as needed, the gearing does not change the power output at all.