It almost seems as if BMW just started selling the current-generation 5 Series, yet one of our spy photographers has already spotted a next-generation prototype in Touring form. Little is known about the luxury wagon in this early stage of testing, but it is expected to weigh much less than the current car, which, in 528i Touring guise with an automatic transmission, tips the scale at over 3,800 pounds. It is also expected to have the latest in driver-assistance technology. Despite the weight savings, and judging from the photos, it looks to have proportions similar to the current car, but don't expect the makeshift headlight and taillight clusters to make it onto the production model.