You can indeed get the AA Amex one, the "Amex" on the card just signifies the transaction network being used, it's not a card that Amex is actually approving. The card is authorized and administered by Citibank.
The 2x75,000 AA bonus cards (simultaneous application) are definitely the best deal going right now, unless you absolutely hate AA miles or something. If you can meet the minimum spends definitely do those first before the US Air or Sapphire cards.