"A 3x2 conveyor as opposed to a 2x2 that can hold much bigger loads"
The Wide Conveyor costs $6k per conveyor when bought from the shop and has the same speed of a Basic Conveyor. As the description suggests, the Wide Conveyor (due to its larger width) can hold a larger quantity of ores. A Conveyor Converter will allow you to transition ore back to a standard 2x2 conveyor.
This is one of the largest conveyors in the game.
Obviously, this conveyor can fit with a Teleporter Receiver.