There is no other zombie killing experience like CO

Nazi Zombies. Those other games are cool, but not as cool as COD Zombies.
The main problem is that the current zombie-mode script doesn't really allow for many of the features people expect in a "main-game" - such as bosses, checkpoints, and level ends. There have been numerous attempts on PC for mappers/modders doing just that, but without success. And trust me, these guys are VERY good at making zombie maps.
My idea for a Zombie-only game is that you play the game backwards (in order of events). You might die every mission, but not a game over (other possibility; travel back in time with enough points/high enough round/defend area for certain time). You have goals you NEED to accomplish to prevent the spread of zombies, after which your death/escape is not in vain. (death without completing goals is game over-zombies win!) Your points (possibly other factors; intel gathered, passwords obtained, keys to unlock areas, etc) effects how you start the next mission, or even better what the next mission is. By securing an area, you stop and contain the disease. To beat the game, you will have to change the events that lead up to the creation and spreading of the zombie disease.
I know some of this is self-contradicting. It's a 5 minute brainstorm. BUT IT WOULD BE #&@$ing AWSOME!!!! Feel free to pass this along to Treyarch, anyone.