The spirit of MtG can be adapted to the D&D ruleset, and I personally think the many planes of Dominiria would make a much more interesting (albeit EXTREMELY OVER-THE-TOP HIGH MAGIC) world than Eberron, or even the Realms for that matter (which I've become bored with). I'd kill for a chance to do that as a stand alone product for WotC.
Truth be known however, the CCG R&D division and the TCG R&D division are kept on opposite sides of the WotC offices for a very good reason folks - most of them do NOT get along (I've heard this multiple times directly from members of both teams). A MtG crossover to D&D has been tried -- TWICE, but fell apart in hopeless bickering between the two sides each time and was pulled before a single page was written -- Well, a few pages have been written according to a source I will not reveal, but they are not being developed for publication, instead they're sitting in some filing cabinet collecting dust in the offices (though no doubt the move shook it off).
Outside of the offices, WotC is painfully aware that the majority of the CCG and RPG communities do NOT get along. Ryan Dancey made this very clear at GC 2000 at the debut of 3e - I asked him during a public seminar on the newborn 3e if there would ever be a crossover. He took a show of hands of all opposed and I swear nearly everyone in the room rose their hand. He then said he could probably go up to the CCG room and get the same response to the same question. Now, it's been 5 years since then, but I doubt attitudes have changed much.
If I could figure out a way to develop this myself without being sued I would, but I can't without changing things so much they are unrecognizable. Wizards isn't going to take a gamble with the potential to damage the profitability of not one but TWO of their biggest lines either.
So folks, in closing, take any rumor like this not with a grain of salt, but with a semi-truck load of salt.