Nope, not yet. It would be a little awkward anyways considering you would need 2 screens AND controls. I don't think it would work at all on a phone. The only way you could get the screens set up is in portrait mode and then you wouldn't have controls unless you slid out the keyboard and had only a dpad. You would still be missing the 4 face buttons on the right.
yes on the ds two screens are vertical. but you also could arrange them horizontal i dont think it would make much difference. just a splitscreen in landscape mode. but i dont think that we will see a nds emu very soon maybe in 2 years or something.