One of the first might be that of the Brazilian President, Dilma Rousseff. He could congratulate her on re-election before expressing thanks for the help in our Convicted Murderer Overseas Experience pilot scheme. On second thoughts, probably we've had enough gags about escaping paedophiles for the week.
Phillip John Smith, meanwhile, might count himself lucky to be alive. According to a report published this week, Brazilian police have killed more than 11,000 people over the past five years, or about six a day.
Key had hoped, of course, that US President Barack Obama might pop over to New Zealand while he's in the neighbourhood, but that's not to be. But we do get a few high-powered Brisbane sideshows. The impressive German Chancellor, Angela Merkel, will be here. (Note on pronunciation: hard G in Angela.) So will the seriously powerful Chinese President, Xi Jinping. (Note on pronunciation: not to be called "Mr Eleven", as an Indian news reader did the other day.)
Amid the swirl of multilateral summiting, and the spluttering Trans-Pacific Partnership negotiations, those direct engagements often bear the real fruit. China certainly seems to have been loading up on bilateral steroids lately. In recent days Xi held breakthrough talks with his Japanese counterpart, Shinzo Abe. Beijing has reportedly all but agreed a free-trade pact with Australia. And while US-China relations are not all rosy, the two superpowers have announced an extraordinary set of deals, on military links, trade and a landmark climate change gear-shift, with both countries in effect pledging to double their commitments on emission reduction over the next 15 years.
The agreement, between the world's two biggest carbon dioxide emitters, is hugely important both practically and symbolically. And it's embarrassing for Abbott, who with Canada's Stephen Harper has dragged his heels through the coal fields and tar sands, blocking the action on climate change that scientists almost unanimously urge.
G21er John Key has never been as obnoxious on the environment as Abbott or Harper, preferring to default to the "we're only little" argument. Key once said: "We never wanted to be a world leader in climate change; we've always wanted to be what is affectionately called a fast follower." Now China and the United States have shown leadership, that fast-follow resolve will be easily tested.
While climate change diplomacy for the moment overshadows the G20, Australian officials are reported to have fought efforts to include any reference to the environment in the G20 communique.
Lobbying from the US and European Governments means it will include one anodyne paragraph, however, full of words like commitment and process and framework and convention.
Abbott would prefer the G20 to stick to its economic knitting, and focus on tax, regulation, trade and growth targets, but politics is politics.
Vladimir Putin of Russia will face pressure over his expansionist appetite in the former Soviet Union, particularly Ukraine.
Abbott's tough-guy rhetoric, relating to Putin's refusal to accept any responsibility for the downing of the Malaysian Airlines jet in Donetsk, will have photographers falling over each other to get the two men, both of whom have a penchant for going topless, in the same frame. In the interests of making multilateral summits more interesting, the best thing to do would be to smear both in marmalade and chuck them in a cage with a bear.
The leaders will also no doubt want to discuss the spectre of a force in the Arab world practising an extreme form of Islam that deplores democracy, subjugates women and routinely beheads sinners for adultery, apostasy and witchcraft.
Not in this case Saudi Arabia, itself a G20 member, but Isis (Islamic State). Obama will almost certainly be working to solidify the support for US-led air strikes.
The chances of concrete achievements emerging from the Brisbane G20 summit are slim, of course, and while it is credited with playing an important role in rebuilding from the global financial crisis, today its role is less clear.
If it is succeeding the G7/G8 as the globe's top table, that role may be, as much as anything, as the site for geopolitical stagecraft, gaffe-hunting, and gathering site for protest, whether that be against global capitalism or Putinesque expansionism.
All the same, 100 years after the outbreak of World War I, it seems churlish not to celebrate the very fact of a cordial and constructive conference of the world's most powerful leaders. And the whole undertaking will certainly be worth it, vindicated for all time, if they can achieve this one thing: persuading Bob Geldof that resuscitating Band-Aid is really a very bad idea.
Hack Pack on track for back-slap at G20
Stephen Harper is in New Zealand today for a pre-G20 stopover. Discussions are likely to centre chiefly on how much John Key admires Canada's flag, and a little bit on how he doesn't admire Canada's hardcore dairy protectionism.
In Brisbane, they will be eager to catch up with Tony Abbott and Britain's David Cameron, the remaining members of the Hack Pack, as they must henceforth be known (not because they like to penetrate firewalls, but because their surnames make the acronym Hack and Hack rhymes with Pack. Okay?)
They have plenty in common. White blokes in their 50s (except Cameron, 48), they lead right-leaning governments in Anglosphere Commonwealth states, united by various cultural inheritances and membership of the US-led Five-Eyes spying alliance. It will be the first chance for many of them to catch up properly since Mandela's funeral last year. Then, a photograph published by the New York Daily News featured David Cameron alongside John Key, captioned: "David Cameron and unidentified guest".
But while he may not have the global profile of the other Hack Packers, Key is the most admired. Conservative Party supporters in each country have noted with slack-jawed envy the electoral rewards brought by Key's style and appeal to the centre-ground. All of them, to some extent, regard former Australian prime minister John Howard as a model. Key has called him an inspiration and mentor, while Abbott has quipped there was an "apostolic succession" from Howard to Harper and on to himself.
The quartet are singing very much from the same hymn sheet on the threat of Isis (Islamic State), too. While the belligerence of the rhetoric varies - Abbott is the most gung-ho and jingoistic - all have stepped into line with US action in Iraq and Syria, warned of domestic Isis threats and used this as a basis for curbing civil liberties.
