I really share this feeling especially during the past 7 months while the fund-raising was ongoing.
Now, to be more practical and maybe start an implementation of a distributed Wikileaks. There are two processes : the submission process and the distribution process. I think the distribution process is easy with Git or any distributed VCS. The submission process is more tricky as this is involving a human/social process to merge content into the distribution "branch".
The submission process could be "à la" HN where there is a way to up/down vote a submission. When the submission is reaching a defined level, the submission is released for distribution. In this is case, the submission network is still centralized but the distribution part is really decentralized.
For submission process decentralization, distributed ticketing (e.g. http://ditz.rubyforge.org/ ) could be used to show status of a submission within a same git repository but showing/merging only submission reaching a level in its ticket. Just an idea...
Update : my humble comment is just on some technical aspect. The social/legal/human aspect of Wikileaks is something much more complex...