From Autocar:
"
BMW will fight back against the recently unveiled Mercedes S-class with a new 7-series that development boss Herbert Diess calls the most technically advanced car in BMW’s history. "
..... " planned launch in late 2015. The new car will receive its world debut at the Frankfurt show in autumn of that year. "
" The new 7-series will ditch the traditional steel monocoque construction of today’s model for a structure that uses a mix of steel, aluminium and carbonfibre. Autocar has been told that this will cause the base 740i to undercut dramatically the 1900kg kerb weight of today’s model,
and potentially even the 1670kg of the current entry-level 5-series. "
" It is expected to be about 5010mm long, 1815mm wide and 1425mm tall.
Two wheelbase lengths will be offered. "
http://www.autocar.co.uk/car-news/new-cars/next-gen-bmw-7-series-shed-weight