According to a report by My Nintendo News, Nintendo has registered a domain name for Super Mario 4. Nintendo registers all sorts of domain names to secure names for future titles, but with the recent announcement that Nintendo is “planning to release a totally new side-scrolling action Super Mario in 2D” for the Nintendo 3DS, a name like Super Mario 4 seems plausible. While this doesn’t confirm or deny anything, it does give us some food for thought.
Although, it’s interesting to note that the Super Mario 4 title has already been used in the Japanese version of Super Mario World, titled Super Mario Bros 4: Super Mario World.
On a side note, Nintendo registered the domain name for Mario Party 10 months ago, but domain names for Mario Party 3DS, Mario Party 11, and Mario Party 12 have all been taken by someone other than Nintendo.