Problem is the oil must be stored below the crank. The volume of oil is a gallon. As such it has a fix amount of room it will take up. you could spread it out paper thin but the pump couldn't pick-up. So it will need to go deeper, which is what the factory did.
All commercial pans except a dry sump which as the name implies is dry with no oil in it have a wet sump of some kind and all are at least eight inches deep. Most go deeper to add oil capacity (more volume than a gallon to account for high volume pumps). So nothing is going to be commercially available or custom made that will work.
So if he wants to get rid of the sump he need a five stage belt driven pump (two scavenger lines from the sump and one each for the valve covers to suck up all of the oil and air in the engine), a reservoir to store the oil, and an oil air separator, and an additional oil reservoir that is changed with compressed air that feeds oil to the mains on start up. All of this can be plumbed any where under the hood but racers all mount this on the front plate of the motor mount to make engine removal easier and cleaner (the mid plate is actually the rear motor mounting plate). And yes this is very expensive.
Most of the Mexicans who bought old Chevys and turned them into bouncing low riders in SoCal just welded steel rails to protect the stock pans so when they drove along at night you could see the shower of sparks as those steel rails drug along the pavement with the car on the ground.