I can totally see a Dark Tranquillity-ish version of A Lesson in Evil... or maybe a version of Drowning in Sadness with some Diabolical Masquerade crazyness thrown in.
I think, "Shadowman" would fit very well. If you would just add growling and downtune the guitars, it would already sound a little bit like some of the melodic Edge Of Sanity songs.
But in general, I would love to hear it the other way Turn some Edge Of Sanity songs into progressive, rocking Nightingale tunes, with clean singing and all! For example, "Twilight" or "The Masque"!