Simba the Lion King.
Did the Disney studio steal Kimba The White Lion and rework it as their "original story", The Lion King? They certainly give that impression with their corporate stance ("we never heard of Tezuka nor Kimba until after The Lion King was released"). And why would they have filed suit to try to prevent the showing of Tezuka Productions' 1997 Jungle Emperor Leo movie at the 1998 Toronto FantAsia Film Festival? (Jungle Emperor was the original title for Kimba The White Lion.) It seems quite simple; Kimba had been kept out of sight in North America for 20 years by that time. And once you can see the two together...
Look at the evidence and judge for yourself. But what gets me, is why would they not admit that it's a remake? Cinderella, Pinocchio, Snow White, Tarzan...the list goes on. Are we to believe that 99% of Disney movies are original, because, you know what...they're not! (If you want some more evidence, someone far geekier than myself went to a lot of trouble. Check out: Simba )
I'll leave you with this thought. Why do they make these terrible straight-to-dvd sequels when they could do this crossover?