Thank you BinarySurfer.
In case I was not clear, I was not comparing AI with stealth technology, merely pointing out the potential secrecy of projects involved in such areas prior to being released to the public's knowledge (unclassified).
There are several approaches to the development of AI. Yours seems to be geared towards evolution, which I would agree the world/environment would need to be defined. However, this could be a predefined rule set given to the AI from which it has the ability to learn, reason, comprehend, solve problems, form its own conclusions, or adapt by adjusting its methods based on information derived from prior trials-and-errors or other scenarios.
I agree with your statement of "no computer will ever have enough processing power/memory". A single computer would never be able to do this by itself, especially if failover is a factor. Think in terms of parallel processing, high performance / distributed computing etc... Imagine a Beowulf Cluster of supercomputers which each box processing >1 trillion calculations a second.
For reference, Check out the Cray XT4.
http://www.cray.com/downloads/Cray_XT4_Datasheet.pdf
In the end... necessity, inspires invention.