Why on Earth would you think that Cafe would ever arrive at Scenario 5? Absolutely nothing we've read in any seemingly credible rumor source has even hinted at such a thing. The best we've seen anyone say (IGN in this case) is that it would be "significantly" more powerful than the PS360. Now, my interpretation of "significantly" may be different than yours, but I never took that to mean an entire generational leap from the PS360. After the Wii, my expectations may be pitifully low, so the fact that some are saying that Cafe would be even 3-4 times more powerful than the PS360 absolutely blows my mind.
The only way that I could except scenario 5 happening is that it won't be the result of Nintendo going the extra mile, but rather Sony and MS going back one. I have no clue what MS is doing (even rumor-wise), but at least for Sony, I don't see them taking a more conservative approach after coming out with the NGP.