Leica SL 100-400mm lens is coming soon. According to the LR, this new lens will be announced with the 1.4x teleconverter.
The new Leica SL 100-400mm lens is rumored to cost $2,500 and is very likely based on the current Sigma 100-400mm F5-6.3 DG DN OS. It is made in Japan.
The 1.4x teleconverter is rumored to cost $999. Leica will also announce a second 2x SL teleconverter this summer.