Something I would call the Wii Strategy.
Without all the media buzz, which included "Wii sold out!!!!" the Wii wouldn't have sold as much as it did.
Did WotC try something similar? I don't think so, but its possible.
The Wii strategy is call blue ocean; selling to new customers rather than fighting over the already existent market. It was helped by the fact that the Wii was a party system and customers became advocates of the system to friends and family by hosting Wii parties. Wii sports was a killer App in this; four player fun for all age groups.
The "sold out" effect may have slightly increased media exposure, but the phenomenal sales were there from the marketing and the device itself.
Is there any actual proof beyond Internet rumor that Nintendo actually did this?
Nintendo definately did not purposely under supply. No way. The are a very conservative company, that has been in business for over a hundred years - making playing cards when they first started. The Wii was not a sure thing, with hindsight it is easy to ask why they didnt ramp up productions, but internally it was seen as a risk.
Ramping up production facilities is not something you can do over night and you have to be sure that the demand will sustain itself or you will end up with a lose; ramping up prodcution costs a lot of money.
Nintendo have increased supply several times to try and meet demand, but demand has been phenomenal. They have sold more than the PS2 in the same time frame.
So no, no way, they did not artificially create this situation.
EDIT: Nintendo have made a profit every one of those years, an amazing achievement and partly due to their business culture I suspect.