We have done it in the past, and it was more of being able to switch fabs at a drop of a hat, not necessarily two at once.Evildeus said:I think RussSchultz said that it was exactly what his company is doing. So i wouldn't say it's not economically feasible
However, if you're a huge company with lots of sales, you don't want your product only capable of being produced at one place. Earthquakes aren't rare in Taiwan, so dual sourcing is semi-smart.