They have been posting patents about potential successors to the 100-400 for at least 5 years. Same about specs list of a potential 7D2 so... I'll get excited when I see a listing on B&H
Better idea -- marry someone who's into antique airplanes. He never asks what any of my toys cost. If I want to know what his cost, I ask our older daughter, who has the same hobby. Hereditary.