For years, the sportiest 7 Series in the U.S. has been the Alpina B7, which has been heavily breathed-upon by the namesake tuner and offered through official BMW dealers. Most recently, Car and Driver reopened the discussion just last month.
While the company still isn't officially committing to an M7, TheDetroitBureau.com quotes Ludwig Willisch, CEO of BMW North America, as bullish on the model's prospects. According to the the report, while BMW has long maintained that it wouldn't build a 7 Series M, "sentiment appears to be changing, especially with Willisch's counterpart in China also lending his support." Of course, if BMW builds such a model, that doesn't mean we'll see it in the States, but Willisch seems optimistic about our chances.
No timetable has been set, and BMW has been occupying its time with the just-revealed 7 Series refresh (and the M division is still busy readying the next M3), so if an M7 is in the cards, it wouldn't surprise us if we had to wait until the next-generation model's arrival.