Longer - after watching this video I was checking out other BMW design studies (ie. concept cars) from over the years. Here's a design study prior to the e38 from 1993:
In more of a profile it looks a bit like a 4 door e31.
Shows they've been toying with the idea for a long time - a bit like the BMW V6 engine.
I saw an article with some BMW engineers a while ago where they were saying that they've designed many V6 engines over the years, each time they bring out a new generation of engines it is considered. The inline 6 designs have always won out in the testing phase so none of the V6s have ever gone in to production.