This video is interesting, bit long winded, but the image stabilisation of the Sony HDR AS15 does a very good job. A new model is just about to come out, Sony HDR AS100v, which looks like a real competitor to the Gopro, but with the added beauty of Sony's image stabilisation and 3 hour battery life. Just use industrial Velcro, to attach it to the side of the Vision camera.
At 97 grams, including battery, it's not too heavy. Plus it can be wifi controlled (don't know if it would interfere with the visions wifi), although most likely it would have to be pretty close to you to do this. But it looks to have some real potential for the Phantom platform in the future.