I have seen talk of this as well. He has a huge contract, and letting him go, and paying his replacement cheep would be an interesting option. I just don't see it though.
Keep in mind though, weren't there rumors last year or so about him wanting to retire? I wonder if this was a warning sign from his pending divorce, and how stable he will be long term.
I don't possibly see how this season is going to go well enough to make firing Sean seem like a good idea. I don't know if it'll be a disaster, but if we win 9 or 10 games without him (the most optimistic I'm willing to go), I can't see Benson canning Payton. Besides, who would they replace him with? It won't be Joe Vitt, that's for sure. Same problems as Payton, not as good of a head coach. If they believed in Krommer, Carmichael, or Spagnuolo, why wouldn't they have used any of those guys as head coach? Who outside the organization would want to walk into that mess? (Especially cheaply?)
Also, I don't think the Saints are paying Sean Payton this year. That might save money. They probably have fired him for cause in March or April, but I don't see them making that stick next year. Also, I think he's pretty popular with the players.
I don't remember retirement rumors, per se. I think maybe you're thinking about the paranoia Saints fans had about him buying that house in Texas last year, and worrying that he wanted to coach the Cowboys? I guess we know what that house was kind of about now.