I beg to differ on the crop factor to be taken into account at all. Crop factor as the name implied means cropping behaviour is involved, as some articles outside clearly indicated cropping has NOTHING to do with focal length of the lens. You don't get a 300mm focal length just because you have a 1.5 cropping factor on the sensor using a 200m lens. Cropping only means less usage of the optical glass, it doesn't lengthen the optical zoom of the lens. If the theory of minimum shutter speed to be revolving around the optical focal length of the lens, then cropping factor should be out of the formula.
Imagine, this, using DX sensor, my hand shake is top and down in total of 1cm in movement, so every pixel in it move by 1cm. Then I crop further, resulting only with 1 pixel by 1 pixel as actual image. so now the cropping factor is extreme. Does it means the 1 pixel this time move more ? or should it still be 1 cm in movement ?
So my observation here is cropping does not gives more optical focal length, so it doesn't result in larger magnitude of movement due to hand shake. If you are comparing between D300 and D700, almost same number of pixels, you definitely know that the pixel pitch of D300 is smaller than D700. It merely means more resolving power on the sensor itself, provided the resolving power of the optical glass is not exceeded.
But I suspect another attribute should be in the formula instead of the cropping factor. It should be the pixel pitch, but I must say given the magnitude of the movement, the pixel pitch is negligible and therefore can be ignored.
Thanks