I know these are "just" Tangent/BBSHD kit builds, but they also use 50A controllers, plus custom-built battery boxes.
https://www.electricbike.com/adams-black-panther-with-bbshd-ludicrous-v2-3-speed-and-gates-drive/
https://www.electricbike.com/adams-black-panther-with-bbshd-ludicrous-v2-3-speed-and-gates-drive/