I'm developing an options site which only accepts BTC. I'm aware of the issues already outlined with a BTC-only futures market (http://www.bitcoinfrenzy.com/2011/05/problems-with-proposed-bitcoin-futures.html
) but think I have a solution - the options pricing model just needs to be adjusted properly. Although my site won't take USD, it will occasionally need to arrange a p2p USD transaction (in the case of exercising an option). What is the best service to use for p2p cash transactions? PayPal still? Dwolla widespread enough?