I was originally hired at WotC four years ago to work on the D&D/Magic crossover project. At the time the plan was to make a stand-alone variant of 2nd edition. Tweet was going to write the rulebook and I was going to write the world book. The whole project came grinding to a halt within four months of my being hired. Maybe a year later it was briefly revived, but this time only as a monster book for D&D. Then that too got the kaibosh.
I doubt such a project will ever see the light of day. The different brand groups at WotC are very territorial and they have never worked well together. After I moved over to minis, we tried to do a Magic minis game. Predictably enough, the effort was a huge waste of time.