I think I should point out that, according to wikipedia (which could easily be wrong), Zod was in the first draft of the story that they developed. When Jude Law declined the role, they dropped him entirely (and I wouldn't believe what a Hollywood writer says; they're known to outright lie all the time people). And while it may never have been confirmed, wikipedia certainly lends the idea some credibility, even if it was just an internet-spawned rumour.
My apologies if there was a mixup. That is where I heard that Zod was originally planned.
Oh, and SR is based off the continuity of elements of both Superman I and II, in a vague history contest (dontcha love it?

).
And while I was on the wiki page, I noticed this:
"Hugh Laurie was cast as Perry White, but had to quit due to his role in the series House, being replaced by Frank Langella."
Yeah, I know its off-topic, but how would you've liked House as the editor at the DP ?