I think a new game would be more fun for the participants, even if zombie rules go into effect at that point. I'm not real thrilled with the idea of keeping this current game going with amended rules, but I'll gladly concede if people feel strongly about doing that.
I have no problems with keeping the main thread a 'safe' zone, but I think that it would be bad form to discuss your own demise unless your assassin brings it up first. Some of the kills have been in forums/threads that not everybody frequents and I think dead men (or women) should tell no tales. If the assassin wants to bring it up, fair game at that point. We all love a little bragging. I think a post where you take somebody out is very fair game. As a matter of fact, I think that's more impressive than a normal 'kill'.
The only issue I'm having with the game as it's currently playing is the emphasis on being the last person, whereas I think being the most proficient assassin is a better goal. As such, I propose this (feel free to weigh in):
Normal assassination: Works the same as now, you have 2 minutes from post time to take them out. Worth 1 point
Zombie assassination: After you've been killed you're not totally out of the game right away. You have 1 minute from when somebody posts to get a kill on them. Worth 2 points
Zombie killer: Returning an undead to the dead is easier, you have 4 minutes after their last post. Worth 1 point
Assassin assassination: Take an assassin out within the 2 minute time allotted, using a post they used to take somebody else out. Worth 2 points
Last man (or woman) standing: Just like it sounds. Worth 3 points
High point total wins. Sound good?