Is there any established way to take a short position on mining return... Example: sell 100GH/s Nov13 @ BTC / GH/s

I see you can get long on cex.io, but this isn't really a GH/s "futures" contract, rather physical delivery, which makes it hard to short (i.e. you need to mine to get the GH/s to sell).

Looks like OTC will be the only option, but perhaps someone knows better...?