You can cash a U.S. check at most AMEX Travel offices overseas. The maximum amount varies by card. You'll get the posted exchange rate for the travel office for conversions between USD and the local currency (which usually isn't very good). At least for Platinum and Centurion products, you're not charged any fees other than what AMEX makes on the currency spread.

Likewise, with an AMEX charge card product, any ATM withdrawals come from your checking account and don't incur any cash advance fees.

If you get really desperate, you can use AMEX Global Assist to wire you money. They wired money to a post office in Israel for me once. Not only did they pay all the fees, but the wire posted as a regular purchase to my AMEX card, so I had time to pay it and (I believe) earned membership rewards points. Note that Global Assist is intended for emergencies and can normally only be used once every six months (though they have assured me they wouldn't leave a card member stranded if they happened to have used the service in the past six months and needed assistance).