Why would they stone Aisha? She never cheated on him.
There was an incident, which is referred to in the Qur'an when she stayed behind while out on a caravan because she was looking for a bracelet she lost - a young man brought her back to the main caravan - tongues started wagging - the Qur'an absloves her of course and I remember reading Zamakhsharis say something like:
"I have never see Allah get so angry as he got in this incident, cursing and threatening those who were gossiping"
Muhammad must have been really pissed LOL

I don't remember the verses off hand I will look it up later for you.
Al Nur (24): 11
[11] Those who brought forward the lie are a body among yourselves: think it not to be an evil to you; on the contrary it is good for you: to every man among them (will come the punishment) of the sin that he earned, and to him who took on himself the lead among them, will be a Penalty grievous.
http://quran.al-islam.com/Targama/DispTargam.asp?nType=1&nSeg=0&l=eng&nSora=24&nAya=10&t=engAnyway, she must really have been his favourite wife for him to believe her. His paranoia was so strong and his ego was big enough so that if it was one of his less favourite wives he would have made an example of her.