How open are banks doing mortgagee sales to extended settlements?

If anyone's had experience asking for an extended settlement, or knows of anyone who has, do tell.

Same goes for other terms like smaller deposit, early access etc.

Government departments are almost always uniformly 30 day settlements, very few exceptions.

Lenders are generally open to 60 day settlements, but you'll have trouble getting any more than that. They don't care too much about the deposit amount, their primary interest is clearing the entire debt as quickly as possible.

You might get an extended settlement if you offer a really good price, but even then it's unlikely because they don't want to hang onto something too long when there's a risk of not settling. If the sale falls over they want to be in a position for a quick turn around.
I recently bought a mortgagee sale house at auction. Terms were 10% deposit 30 days settlement, at the inspection a week before auction I spoke to the agent re terms and he advised varying terms should be acceptable. So on auction day at registration I put 5% deposit 42 days setttlement and they were fine.

Whether they would take say 90 days settlement would be a different story.
Last year I purchased a property at a mortgagee sale auction which had strict 30 days settlement. Won the auction but didn't have the cheque book on me so myself and the agent went to my office around the corner to sort out the deposit. Once there I gave him the cheque and asked for a 90 day settlement. He was ok with that but said would have to check with the vendor's (bank's) legal team. They didn't want to hear about it and were so strict to the point where they told the agent to just give the property to the underbidder. Luckily we were in my office and not still at the auction. So I got my solicitor to call the bank's legal team directly and after 2 long hours on the phone they agreed to give me a 90 day settlement. I don't know what my solicitor said to them but it must have been damn good.
So poor agent who missed out on two opens that day since he was stuck in my office for two additional hours finally got his signed contracts and I got my property on a 90 day settlement.
In summary I would say it can happen (depending on which bank) but it's not going to be easy if it does.

Difficult, not impossible.
i have 'won' a mortgagee auction in the past being highest AND only bidder, but did not meet their minimum bid. If that is the case, then they normally negotiate with the highest bidder. I didn't take the deal, they wanted way too much $'s verse the work that needed to be done to it... but i believe in those cases they would be negotiable for settlement dates as well.