BMW has already announced a new eco sub-brand that will exclusively consist of electric cars and hybrids. But BMW has its sights set on electrifying its motorcycle lineup as well. The BMW Motottad Concept E is an all-electric emissions-free scooter that made its official debut this week at the Frankfurt Motor Show. The 60-volt concept is good for about 60 miles on a single charge, and it can be fully recharged in just three hours. While its electric powertrain will undoubtedly boost BMW’s eco-cred, the automaker says it will still deliver performance that’s on-par with a 400-500cc commuter…