OK, I'm officially really confused, because I'd heard about this project before on Ain't It Cool News, back at the start of April, The catch; it was confirmed to have been part of an elaborate April Fool's by the news blog Upcoming Pixar. ???
If you scroll down to the bottom of
this page from Upcoming Pixar's April archive, you can see the two-part April Fool's post (the first stating that the blog had been purchased by Disney to be the official Pixar blog, the second revealing the John Carter of Mars project as the site's first announcement under the new agreement), and for further reference,
here's the corresponding news item from AICN's Moriarty. I saw both of these articles after they had already been debunked as pranks, so I didn't think any more of it.
Yet now this! It's now May 1st, so it's waaay too late to be a joke this time...my first instinct was that Daily Bulletin had merely picked up on the month-old prank and ran it without checking, but then they went and actually got a quote from Bird that seems to confirm it! Could this April Fool's joke have somehow miraculously come true?

Frankly, I'm baffled over here...I'm guessing from the sounds of things that Upcoming Pixar's original April Fool's story was itself constructed from a number of strong rumours circualating at the time, hence its believability; it seems now at least some of those rumours have proven to have substance. Having said that, I'm still not sure how much of this might still be conjecture or misinformation; it doesn't seem like Bird himself actually said anything about John Carter of Mars, so I wonder if that's just a flawed leap of logic on Daily Bulletin's part...
In any case, this is a development worth monitroing. For my part, I'm interested in anything and everything Pixar and Bird so I'll be all over this if it's true, but for now I'm going to wait and see...