Outgoing president of Iran. Could bring to the role a moral authority not seen since William Hartnell told Ian and Barbara not to interfere with the Holocaust because it probably didn't happen, or if it did then the Jews were probably asking for it anyway.
Outgoing prime minister of Zimbabwe. Insiders say he is desperately keen to take on a new role, and keenly desperate to take the first flight out of Harare International. Could be entertainingly chased all over the cosmos by minions of the Black Guardian (Robert Mugabe).
Ongoing Mr Queen of Great Britain, Northern Ireland and of Her other Realms and Territories. Would bring 92 years of supercilious cheek to the role, calling Daleks "wogs in tins" and quipping that the Cybermen can't be made in China because only their mouths are slitty.
The Outlaw Jimmy Wales
Put-out founder of Wikipedia. Likely to spend his time fighting his former friend the Porn Master (David Cameron), and explaining everything in laborious - and often wrong - detail. Bonus: already used to dwindling budgets.
18-inch talking robot, purpose-designed for space adventure and providing a feeble pretence of belonging and companionship to lonely middle-aged men who don't get out enough.