I feel your pain... literally! Esme is also a biter! I have decided I am just going to have to wait until those sharp puppy teeth fall out.
Luckily, she is only biting when playing, it's not aggresive, but it still hurts just the same. I have tried EVERY method you have, and nothing. Biting is her only flaw, other than that, she is PERFECT.
Esme will be 6 months next Thursday... I hope we can overcome this stage soon!