That's exactly what is happening, there is going to be a new formulation of 0w40 that passes Dexos specs so it can be used as factory fill on the 2019 Corvette, which starts production on Jan 29, 2018 (which kinda bums me out because my brand new 2018 isn't even built yet and it's going to be one model year old almost as soon as I get it)
I sent an email to Mobil asking them for more info on this oil (technical specs, when will it hit store shelves) and heard nothing back.
GM is going to allow it to be backwards compatible in the 2014 to 2018 Corvettes as well, so even though my 2018 will come factory filled with M1 5w30 I plan on switching to this new 0w40 when I can get my hands on it. To make life simple, I also plan on running it in my wife's BMW (no point in having two different 0w40s and possibly putting the wrong one into the Corvette by accident)
At first when I heard this I did not believe it but I have now seen a picture of the Corvette's new oil filler cap which says 0w40 and Dexos on it so it's the real deal folks!
I think one of the reason they came up with this was because GM's recommended procedure for guys that wanted to race their C7 Corvettes was to switch over to 15w50 for those events, and then switch back to 5w30 for street driving. Now this allows everyone to just run the same oil all of the time and it should be able to work well for both situations. But it also allows GM to have some bragging rights, as they finally will have their own oil specifically formulated for use in the Corvette.