In my opinion, it has already been proved beyond doubt that Nintendo is stockpiling Wiis. The best evidence for it is the fact that Nintendo changes supply to account for big game releases.
Regarding your other question, of course stockpiling is important and the right strategy. Nintendo wants to (and will) see headlines such as:
"Nintendo wins holiday season"
"Nintendo outsells 360 and PS3 combined by 1/2/3/whatever to 1 in the holiday season"
Besides, Christmas is a battle for the consumers' money, since many people WILL buy another console if they can't find the one they want. This factor doesn't seem as important to me because the different consoles have difference prices and styles, but it will likely become more important with the upcoming price cuts and casual titles getting launched for the 360 and PS3.
My Mario Kart Wii friend code: 2707-1866-0957
