Tamron filed a patent for a teleconverter with a built-in image stabilization. This will allow to add image stabilization to any existing/old lens by just adding this teleconverter. The teleconverter range was listed as x0.9 - x1.5. The patent describes also a switch that can turn on/off the image stabilization.
Update: this patent was filed back in 2001 and Nikon had a similar patent filed in 2002.
