Zhang/Reynolds/Fernandez/Kovtun/Hanyu/Goebel/Joubert/Honda/Klimkin have all done at least one program with two different quads landed.
Also, I said they landed it, not mastered it. There are plenty of skaters who haven't mastered triple axels (e.g. Chan/Lambiel) but they still attempt it. If skaters only did elements they've mastered, then you wouldn't even get skaters trying any quad (as many of the top men have yet to master them). I don't expect most of the men to have mastered 2 quads, considering most have to master even one type, but they should still be comfortable enough to compete two different quads (obviously the risk is always there when competing quads).
A man doing 2 quads of the same type is fine, but I think men should be challenging themselves to try another quad. Just like for a while it was fine for a man to just do 2 triple axels and avoid the quad, but they should slowly attempt to bring the quad into their repertoire. By 2018/2020, we should be seeing the men at least committed to getting two different quads and starting to bring that into competition (18 years after Goebel landed 3 quads at the Olympics, mind you). I would not like to see a men's competition in 2018 where a FS with just 1 quad and 2 triple axels was as ambitious as any top 10 skater wanted to be.
I would hope by 2018 the planned/attempted FS layouts are something like: 1 quad and 2 axels for top 10. 2 quads and 1 axel for top 8. Either 2 quads + 2 axels or 3 quads + 1 axel for top 5, and 3 quads 2 axels as a podium standard. No quad attempt or just one quad attempt that was failed = out of the top 10.