Since the posting of this question, Nikon has put out a new lens for the nikon 1 system: the 1 nikon 70-300 f/4.5-5.6. Due to the crop factor, this actually comes down to a massive 189-810mm focal distance. I don't have much experience with it, but from what little I used it, it is much lighter than most DSLR zoom lenses, but it suffers in low light conditions due to the camera itself and the wide minimal aperture.
I think that if you're accustomed to the 30-110mm in terms of light performance, you can expect the about the same with the 70-300. It will probably perform pretty well in good light conditions, but getting birds in flight might pose a problem.
Another concern might be the price point, currently, I'm looking at a €1000.- price tag which is over double the price I paid for a nikon 1 v1 with a 10-30mm kit lens. In the end it comes down to preference: if you have quite some nikon lenses laying around, the FT-1 adapter is a reasonable albeit pricey alternative. If you want to have a load of extra zoom, but still the same light performance and a pretty low weight for it's focal range, the 70-300mm is a reasonable choice