Interesting discussion. We were in Greece in June and were able to get cash from the bank cash machines easily. The only time we had a problem was when the cash machine was not attached to an actual bank. These machines are not serviced regularly and sometimes run out of cash. We were able to withdraw as much as 500 euros at one time the limit set by our bank in Canada.
Larger hotels will take credit cards. They will ask for cash but if you press they will take credit cards. All hotels have a sign in the lobby stating if a receipt isn't provided then the customer doesn't have to pay. Sometimes they forget so do ask for the receipt.
We were in a remote village in Crete and asked if we could use credit card. The owner told us that all his suppliers and staff demand cash payments. With the cash withdrawal limits imposed on Greeks a credit card payment hampers his ability to operate. We heard that story from virtually every shop and taverna. We just paid cash from then on.
mtcarroll it isn't clear to me if the hotel is asking you to pay them cash when you are there or if they are asking for an advance payment. If it is an advance payment then you really have no choice but to use a bank transfer, credit card or Western Union to transfer the money. That solution is the problem your hotel is trying to avoid.
However if the hotel is saying just pay cash when you are in Greece then you will have absolutely no trouble getting cash from an ATM machine.
Greece still is a predominately cash driven society. I am pretty sure someday the Government will impose credit card only payments simply so they can get their hands on more tax revenue. Until then you should expect to be paying cash at small hotels and tavernas.