Last year via Coming Soon Nintendo released some concept art for Super Nintendo World at Universal Studios Japan.
According to the trademark application filed, REAL LIFE MARIO KART could be in the works. In an article from Nerdist, they do state that Nintendo CAN choose to not act on Mario Kart. A trademark is just essentially where a company lists everything that could possibly come under the trademark. They listed tons of other stuff like musical performances, video games for both handheld, consoles, and mobile devices, and entertainment shows.
Basically, this theme park is my personal dream come true and I need to start saving for my trip to Japan ASAP.