This was always one of my favorite initiatives and I am glad you are bringing it back! :)
Reposting old posts could work, though some might considered doing that a downvote worthy offense.. Perhaps if the old posts are only reposted within the community and not to our blogs, it could work out well. Keeping it structured as a weekly contest would probably keep it easier to organise, with relatively specific parameters as to the quality of the post that can be submitted. The regular people participating were always good about only supporting quality posts from what I remember anyways. Either way, however you choose to bring it back, I look forward to the Deadpost Initiative coming back again!!