Re: how many slams do the following playing have in them?
Fed = probably 1 more tops. As much as I'd be happy for him to keep winning slams (and he did show he can still hang with the top guys at the AO) he's going to continue his steady decline and will have to be sure to grab his chance if it materialises.
Rafa = I could see him claiming as many as 4-5 more. He's still going to be favourite at the FO for a while, and depending on health I don't think you'd really count him out of the other slams, especially with his mentality.
Novak = 5 more at the least imo. He's the dominant force in tennis right now, great on all surfaces, is at the peak of his career, and he holds a mental edge on the hardcourt rival who's likely to stick around to challenge him.
Murray = could have said a lot before the AO final, but another loss really makes me question how reliable he will be as long as the other guys are there to mount a challenge.
Of course this is all dependant on the younger generation continuing to fail to make any inroads at all.