Is there any reasonable way to short-sell Bitcoin It is not an official currency (yet?) but definitely has a market, and as such, I might be intrested in short-selling some. Are there any reliable, way to bet against it?
Even though I would strongly advise against it doing a search turns up:


https://icbit.se/ 
http://mpex.co/




There are probably others but do take into consideration that the majority of these "exchanges" have statements like the one listed bellow (taken from https://btct.co/faq):


  Is it legal for this exchange to operate?   (...)
  
  
  No assets on the site are to be considered real.   
  The use of this site is for educational and entertainment purposes only.   
  If an asset issuer on this site defaults, you have ZERO RECOURSE. (not like you have any recourse in most international BTC situations
  anyway.)