I would be happy to see a source release early in the new year, once we have a majority of people able to use the software and its basic functionality without it breaking(broken software is never good advertising, even if it's open source).
I don't expect clones to come out of the woodwork immediately regardless of market cap, because the Bitcoin clones are based on being familiar, disposable, and easy to market to the unwitting. With a completely different codebase and some new concepts that go against the grain, Nxt won't be a prime target for cloning until it's in very safe territory.