I bought my adapter from Rob at vaporcountry(.com).
It works great, it was only 5 bucks, it gives me the same amount of power as my PC as far as I can tell, and has yet to fail me.
Too bad they're temporarily offline...
Maybe you can ask him where he gets the ones he stocks?
He may not be making any sales right now, due to the whole paypal fiasco, but I don't doubt that he'd be willing to help you out.
Edit: Rob is taking orders as of yesterday, check out this thread:
Let me know if you need anything