Updated Feb 11/21
Metabones Adapters for the Pocket 4K

Metabones Canon EF to BMPCC4K T Speedbooster
ULTRA 0.71x - $879 - special order
Metabones Canon EF to BMPCC4K T Speedbooster ULTRA 0.64x -
$879 - special order
Find Metabones rail support here
Find more lens adapter
here