I disagree about Golarion gods.
Abadar is the God of Law, but that's law in the legal sense, not law in the alignment sense. He's no more the god of law (the alignment sense) than Irori is.
I'd also argue that Sarenrae could easily be the goddess of Good. And, of course, Iomedae is explicitly the Goddess of Paladins (even if not of Good and Law).
I think, though, an important thing to remember about making 'Paladins of other alignments' is that Paladins are defined by what they oppose as much as what they are. The default LG Paladin fights Evil. But an LG Paladin who fights Chaos would be different. On the other hand, making a CG paladin could be done without actually changing any class features, as long as they oppose Evil and not Law.
Should an LE (anti?)paladin fight Good or Chaos? Do we need a CE antipaladin who fights Law instead of Good?
I for one find the names for the alternate alignment paladins to be kind of a clue for an elegant system for this: The normal paladin is LG, but is good over lawful and fights against evil. The Paladin of Freedom is CG, and fights against law from the angle of good. The Antipaladin (of Slaughter) is CE, but evil in a chaotic way more than dedicated to chaos and fights good. And the Antipaladin of Tyranny is similar to a Hellknight, chiefly concerned with Law and fighting against Chaos, but is evil in the way he carries it out and must eschew mercy and goodness.