sounds a bit like excessive AJAX overuse. With 60 AJAX Pages on one Page it could bust your Session (Memory) Size. Per Menu-Item a Page (with Page-Reload) is a better approach.
I'm gonna agree with Mark that you should better try to split all the logic on separate pages. But it depends on your requirements. Because if your customers want to have so many AJAX calls probably they won't agree with Mark's advice.
I also want to warn you about using keepAlive tag because what's gonna happen if a user will refresh page or go to another site and then again to your app. Is it OK that all data from keepAlive beans could be lost(Think about storing some data in Session and App scopes)?