Neither Jimbo Wales or the Wikimedia Foundation could bring forth such a lawsuit, because libel is "an untruthful statement about a person, published in writing or through broadcast media, that injures the person's reputation or standing in the community," and Wikipedia is not a person. However, if Wikipedia was a corporation, it could be argued that since the Supreme Court ruled that corporations have a right to freedom of speech as persons, they also merit protection from libel as persons.
As to whether there is any merit to such a suit, or for the argument to bring forth such a suit in the first place, that would be a question for a judge or a jury, and you didn't ask anyway.
I'm tempted to think that you're one of the Ten Thousand Argonauts, but at the end of the day, that doesn't matter: a question is a question, regardless of who asks it. That's a concept that seems to be beyond the grasp of most Wikipedians, who seem to operate under the curious notion that the validity of something depends exclusively on who said it.