Guy:
We had a chance to discuss this internally.
We do not have much to share. We think it may be possible with server-side extensions, but there would be many questions that have to be investigated and answered. The server-side depends upon Guice dependency injection and we aren't sure what the impacts of dynamic classloading and extension reloading would be on that. We are not in a position to do a deep dive investigation on this topic until after we ship the 4.x release later this year. We are not yet in a position where we even have all of the questions that we should be asking. It's one of those situations where we need to sink our teeth into this for a few weeks so that we can come back with a clear understanding of the problem at hand.
So the conclusion is that we think it should be possible, it's wading into some tricky waters, and we'd need an extended period of investigation + implementation time to make it solid.
Can you tell us more about the problem that you are attempting to solve with dynamic extension deployment?
Tyler