These same rumors were being floated around Bill Clinton's last year in office. I don't know whether Bill Clinton really tried for it either. But it was always a very unlikely long shot because...
1. Most of the UN already thinks America has way too much power. Even assuming Obama got OIC backing, I don't see anyone else unfriendly to the US signing up for Team Obama.
Yes, Obama has done plenty of damage to America. But countries that hate America also tend to be on the hostile and paranoid side. These days they might sign off on Carter as SecGen (and maybe not even that), but they wouldn't have done it right after he left office. Even OIC support would be far from certain now that the Saudis and their allies hate Obama. And Turkey has its own grudges.
Russia hates Obama. Portions of Africa liked Bush better. China wouldn't want any American. And if they had to pick an American, it would be someone more rational.
In short, this isn't on anyone's wish list. I doubt it's even on Obama's wish list.
2. The job isn't that easy.
Yes it encompasses a lot of traveling to foreign countries and attending parties. But it also involves everyone in the world complaining to you, without being allowed to yell back at them. In short, Obama would hate it. There are plenty of opportunities for corruption, but unless Michelle is planning to pull a Hillary, it would seem to be superfluous.
Obama could get better gigs that are more fun, pay better and let him spend more time around his fan base and his golf courses. This is the sort of job that Kerry is insane enough to want. Obama might like the title, but the practical side doesn't come with that much prestige.
He might want a gig that would let him do something similar, take trips around the world, meet with leaders and attend parties, but it would likely be more casual and less task oriented.
Obama barely wants to attend to major crises now. Do you really see him wanting to fly off to Burma or Ghana at short notice?
3. The source is the Kuwaiti newspaper Al-Jarida, which somehow knows more about what Obama and Netanyahu are doing than any American or Israeli papers seem to. Its history of scoops haven't exactly panned out.