Wait, you can create a 2D Array of a struct (a single commodity class that extends from System.ValueType and that has an enum variable that indicates commodity type and float variable that holds the relevant information. you need to make it serializable for an array of those to be editable in the inspector). That way you will be able to resize and add to this array in the editor (which I think it's the right solution for your problem). It also allows planets to have more or less commodities (since the array is of no fixed size) which adds to the flexibility of the design...
