A more important point is that even if you make up a god for your character to worship, by the rules you are not playing your own god; it's your GM who plays their part and thus decides whether your cleric is succesfully following their code of conduct.

Trying to come up with a god that'd specifically let you get away with anything and everything you want to do would be a pretty blatant attempt at gaming the system and grounds for your GM to say "Haha no. Just use one of the established deities or be a conceptual cleric".

Being a cleic of concepts is the actual 3e loophole you want to use when no god would fit your purposes. Which is a great reason to to ban clerics of concepts.