"Even our grandmother could tell you that Nintendo is working on another Mario Kart game."
For all the stupid will Nintendo make another Mario Kart game threads...
"But with the company's other major franchises already dominating the scene, is it too early to show off another big gun?"
That's what I've been thinking which is why I don't think it can/will/should come out untill atleast 2009.
But play france is awsome so ya, their rumors have a higher chance of being real then most.