I'm not sure in regards to it being floated. I'm assuming that it means they would own the Bitcoin 1 for 1 for how much someone is purchasing instead of doing some fractional reserve system of the underlying asset.
From what they were stating it wouldn't really look like an ETF would ever get approved because they stated a lot of the trading happening on exchanges outside of the United States and all that. Really when it boils down to it they aren't going to be able to control it as much as they would probably like. They can't control the mining or the resell of it.
Well the announcement has been made for the Winklevoss' attempt but there is another group that still has their application in but I don't see how it would go through based on what was said.