I believe that once the mod API comes out, it might be possible to re-add kiwiships. They would most likely be entitys, similar to the zeplin's mod or ugocraft, in order to reduce the lag on the server. We could make is so the blocks for the kiwiship are simulated in a different environment, so anything that would effect the ship (punching blocks, redstone, TNT, etc...) would be simulated in that separate environment and reflected in a change in the entity. This would reduce lag tremendously and still allow for dynamic kiwiships. However, this would only be practical to implement once the API is released some time in the next 10 years