Sounds like a very intriguing premise. It was previously reported that Matthew Vaughn was likewise blown away by the concept and wanted to make it his next feature film. It's generally assumed that Jane Goldman, the screenwriter for Kick Ass and X-Men First Class would pen the script. Goldman just coincidentally happens to be Ross' wife.
It was also previously reported by Deadline that Vaughn wants Clint Eastwood, Jack Nicholson, and Warren Beatty to star.
From Deadline: Kick-Ass and X-Men: First Class writer/director/producer Matthew Vaughn tells me that a major Hollywood studio is very keen to fully fund his next big project: The Golden Age about a retirement home where superheroes end up. And the title is also a reference to early comic books of the 1930s when Superman and Batman first appeared. It’s based on the yet-to-be-published comic book written by Brit TV chat show host Jonathan Ross, who’s a huge comics buff. Vaughn is currently in LA editing X-Men: First Class for Fox, but tells me he wants to get actors attached to the new project before the script is written. His wish list is Clint Eastwood, Jack Nicholson, and Warren Beatty to play the retired superheroes who help out their grandchildren when their middle-aged parent screw up the world.