Defamation Law

So there are two variables in these cases - private or public figure, and speech on a matter of private or public concern. Private figures speech generally get less 1am protection than public.

Running through the combinations we get this:

• Public figure and speech on a matter of public concern: NYTimes v Sullivan, Butts, Walker - tell us that we need actual malice (something more than negligence) in order to succeed.
  
  
• Private figure and speech on a matter of public concern: Gertz v Welch. We need something more than strict liability for compensatory damages and actual malice for punitive damages.
  
  
• Private figure and speech on a matter of private concern: Dun & Bradstreet v Greenmoss Builders. Less than actual malice will support presumed punitive damages.

So what happens with a public figure on a matter of private concern? What would that even look like? Someone claiming Brad Pitt once filed for bankruptcy? Someone calling Brad Pitt gay? Saying that Brad Pitt took a dump on somebody's lawn?

Or maybe it could only happen in the context of a limited purpose public figure. Like saying that the guy Cheney shot was gay or took a dump on somebody's lawn once.

In any case, what standards apply?