Compact 48V UAV Power Management

I’m building a shared Power Management Unit to run off a 12 S (≈ 48 V nominal) lithium-ion battery pack used across my autonomous UAVs and small UGVs. The board has to fit inside a 86 mm × 55 mm envelope,... (Budget: $250 - $750 USD, Jobs: Circuit Design, Electrical Engineering, Electronics, Embedded Systems, Manufacturing Engineering, PCB Design and Layout, PCB Layout, Thermal Analysis)