But maybe there is a smarter way to do this. Consider this:
Let's assume Alice finds Bob and says "Hey, Bob, I know you like the risk so here are my btsx, please take care of them. I don't care how many btsx will be left when I come to get them back. All I care is that they maintain their value in the future as it is now."
And Bob says: "That's fine, I'll be glad to do that. So I am taking your btsx and here is a receipt you need to show me in the future to claim your btsx back. I cannot promise how many btsx will be left but I can promise that their dollar value will be as it is today."
Both parties should be happy to make a deal because this way they both get what they initially wanted: Alice is hedged in case the market price goes down and Bob is able to keep the profits from Alice's btsx in case the market price goes up. Obviously the opposite is also true: Alice will have to give up any gains on her btsx in case the market price goes up and Bob will have to cover (using his own btsx) Alice's loss in valuation on btsx in case the market price goes down.
And here comes the final trick: we can see that Alice's part of the deal with Bob has a constant revaluation in terms of USD so we can package it as a separate asset and call it "bitUSD". What's more, we can make it transferable to other people - this is possible as from Bob's perspective it doesn't really matter who the counter-party is, all he really cares for is that his part of the deal is unchanged.