[mlubin]

A couple of projects have looked at solving the trust issue by implementing a distributed exchange without counterparty risk on top of the bitcoin blockchain: https://www.counterparty.co/ http://www.mastercoin.org/. The idea is that the protocol itself handles escrow and matching orders instead of going through a centralized exchange.

[oillio]

This might be workable with an exchange (there still needs to be trust in the guy holding the USD). However, options markets require margin accounts. It is pretty hard to offer anyone credit without a lot of trust.