I do not think that Letterman will do the "Vintage" era. That would look like they are copying NBC's The Jay Leno Show.
But I think it would be great to run a weeks worth of shows that origainally got their highest ratings. Like Daves return after open heart surgery, the night Oprah 'returned', Drew Berrymore exposing her tah-tahs and of course Madonna using the f-word like nobodies business.
Then maybe edit together a show of music guests, then comedians doing their routines. Maybe a week of Bruce Willis, Steve Martin, George Clooney and others that do specialized segments for the show.
Maybe even have a weeks worth of shows that they dropped stuff from the roof, when others do the top 10, stuffing people in costumes in places, small town news, Rupert doing crazy things to people, etc.