So instead of focusing on the controller itself, let's think about what is inside. If we are to have an entry for such a thing, it should be an entry that anyone can use... That makes pictures an interesting things for now, but it may be best to use the gallery to put your pictures into, and the entry will have to be more generic. And if you add the item to your collection, you'll have to use the notes field for your specific details.
If the item is housed within a shell of an existing item, but you repainted it, or replaced insides to any amount (buttons count as insides), then you would add the existing item to your collection and set notes to reflect why yours is different.
If the item has the internals of something and you changed the outside, then this could be a separate entry, but the item in the database would not be the item as a whole, but the internal portion that is common. For a controller, this is going to be the PCB inside, so let's hear some opinions about how such an entry should be named, and what pictures we should allow for such an item.