Although wave spectra have often been used in MD presets, bargraphs were not feasible before the introduction of the ns-eel language extension two years ago.
It is certainly possible now to make presets similar to the classic spectrum analyser, but I am not aware of any. Why don't you learn to code milkdrop and give it a try ? It's rather easy.
As to milkdrop in dualscreen, I remember that problems were reported here on the forum with certain configurations, but in principle milkdrop can run dualscreen. Just try a youtube search for a demo.