I am having a hard time finding a live plant package supplier. The type of packaging I am looking for is the type that Burpee (and some others) use. They describe it as follows:

ships live vegetables and herbs in a protective shipping carton made completely from 100% recycled plastic with a secure, innovative design that locks each plant in a separate compartment and then locks the entire container closed. The compartments are designed to fit the 3" pots in which your plants are grown, and a built-in shock absorber within the carton provides added protection from shaking and jostling during the shipping process. This design also guarantees no soil spillage during the transit, so you do not need to worry about dirt spilling out of the cartons when your plants arrive. Each pot is fully protected and locked into its individual compartment; the soil remains completely in the pots no matter how much your plants are moved, shaken or jostled during transit.

The protective shipping carton is placed inside a well-designed corrugated shipping box that ensures your plants will arrive in perfect planting condition.