As for the ODD issue... I've read and read and read on this thread, and I just don't get the issue. Why is the ODD in the iMac so desperately offensive to everyone. You can't even see the thing. Put a piece of tape over it if the slot bothers you. If taking it out will drop the cost $100 or more, sure, get rid of it. If not, why have less machine for the same money? Taking it out is not going to improve the machine any, and it could be handy for legacy apps for a couple of years. The whole argument just seems pointless.
Doesn't sound like you read any of the anti-ODD posts in this thread at all. Either that or all of it just went right past your head. Won't improve the machine at all? Where have you been? When the Mac Mini finally dropped the ODD, users got the chance to purchase some awesome BTO options including double internal hard drives and a discreet graphics card option. Please, I will gladly take more performance over a media reader I no longer use anymore, thank you very much Apple.
And no, putting a piece of tape over the slot doesn't do anything to clear any of the space inside.