A couple big things happening for Winklevoss in my opinion.
1. CFTC officially declares bitcoin a commodity. Useful for the ETF because a couple times the Winklevoss' said the SEC is debating how to classify it. And they are following the structure of the gold etf (which is a commodity as well)
2. Bitlicenses starting to be issued. If Gemini gets one, they can launch the exchange.
What would be a realistic release date in your opinion? Personally I'd be surprised with 2015.