Citibank and ANZ give the large amounts. HSBC was reduced from 5 mil to 2 mil at the ones I've seen about a year ago or maybe 18 months ago. Local bank ones are all small amounts. I didn't see any ANZ or Citi ATMs in Da Nang city outside of the airport, but didn't comment as I had no experience in/at the airport. In Hanoi though I have no trouble finding ATMs.

Here in Saigon a few of the Citi ones have been removed, but the airport has 2 and there are some around the city if you know where to look.