I'm pretty sure Iwata would think you were crazy if you suggested such a plan to him. There's no benefit.
1. Retailers wouldn't be impressed, because they'll know they got shorted on DS shipment numbers.
2. Nintendo cares about making money, not silly PR stunts that the 0.001% of their customer base that was even paying attention would dismiss because it was a supply fluke, not a trend.
3. PS3 sales being obliterated by the sales of two Nintendo systems each by themselves makes a much better headline, even if it's based on Sony's suppy problems.
4. Slowing DS sales is highly unlikely to transfer demand to the Wii.