Used Diving Compressor

I want a cheap/outsource place for some engineering R&D work. (To create a portable air compressor for diving)?
I want a cheap/outsource company for some engineering R&D work to create a portable air compressor for diving. Ideally a lower cost country, like china, where someone can knock me up a prototype. Uses normal technology put together in a novel way. Just a battery + compressor + tank. Need it to be made portable and energy efficient. Just don’t know where to go who could give me a good service.
Why don’t you just modify a 12v battery-powered tire compressor?
No need to sound all uppity with “outsourcing”. If you have any engineering/mechanical skills, you can do it in a weekend in your garage.
Evinrude Aquanaut Diving Compressor