Oh, neat idea! I think you should keep the signature at the end as opposed to a pen name; it emphasizes the "twist" to have the author be obvious. (And since it's written only six months or so after Superman has appeared, it's not likely anyone in Metropolis would realize it was written by Clark.)
I don't know that it needs a sequel -- as much as I, too, found myself grinning over Lois's potential response, continuing might take away the impact of the one-shot. But I guess it depends on what you come up with and how it flows.
Nice job.
Kathy
