I'm still surprised we haven't heard anything official about a PS4... The PS3 came out 6 years after the PS2 and it has been out for 5+ years already.
That said, this seems like a pretty smart move on Nintendo's part. They get to release hardware thats not the most expensive/fastest available, but still beats the current market, and gets to live at the top of the performance chart for at least a few years.
The PS3 was announced about 18 months before availabiltiy, so we actually should be pretty close to an announcement.
In short, I think the 10 year horizon might actually be too short.
But forget all that, you want to make money off of a Farmville clone.