Souleiman is the closest guy to being a true 800/1500 guy right now. And by that I mean his performances in both are about the same quality. Not that he focuses on the 800 before the 1500 like Ventolin says that means (before he jumps in).
The conversion you are looking for is 2.04 to be the 'perfect' middle distance runner. That potentially puts you around WR quality in both events at the same time. Very difficult to actually achieve. It may never be seen again.
But Souleiman and Cram have shown that it is possible to run world class times with around that particular conversion. So one could say it is possible to be a little faster than they were in both events.
Something like 1:42.0 and 3:28.0
You could potentially do the double in Rio off that. Souleiman is the only guy I see possibly achieving those times in the near future.
I have a sneaking feeling Makhloufi may drop some bombs in the 800m too this year and 'come in line' by breaking 1:43.
If Kiprop breaks the WR, say 3:25.5, then I'd expect him to also run ~1:42.5 based on past performances, which would make him a pretty strong middle distance guy but leaning towards the 1500.