One of the types (A I think, looks like the pods on the BFF-1) is created when a space station is recycled. Otherwise, you cannot make them. They are not producable, nor appear in any other fashion.
Its speculated that they might be a way to modify various haulers (ie BFF-1, GR-75, Mod Con, etc) by switching pods to change their cargo cap. But nothing official has been stated on them at this stage, beyond them being put in prior to a planned use.
At this point the can be assigned just as ships are. And can serve in much the same role as escape pods have been used in the past, to grant secure access to items for sale. They work well for item and RM sales, not so good for Droid and NPC sales though.