Back in 1984 Marvel was under negotiations to aquire a number of DC Comics characters, with Superman being among them.
Things went so far that John Byrne actually submitted a plot for his own Superman title at Marvel; however, that would never see the light of day -- until now.
Jim Shooter, then EIC of Marvel, posted some of the details on his blog.
Here are a few:
• Lara-El survives the destruction of Krypton, and with Kal-El makes her way to Earth where she dies in childbirth.
• There is a mysterious form of radiation (in addition to the yellow Sun) mentioned which has to do with the powers Kal-El receives, but never named.
• At the age of 10, Clark takes down a Bull who attempted to kill him.
• While working as a reporter for the Daily Planet, Clark investigates the kidnapping of the President, where he uses his powers to alert the authorities -- with the Pres. being harmed during the rescue. This leads to Clark realizing he should have done it himself.
• He performs numerous rescues and saves, with Lois Lane being present at one in particular. She wants the scoop, but he tells her he gave the story to Clark Kent.
• In the papers the next day, Clark names himself "Superman" via the headline: “SUPERMAN! MYSTERY HERO PROMISES TO BATTLE FOR TRUTH, JUSTICE AND THE AMERICAN WAY."
• Lex sees the article and decides it's best to get rid of him.