There's a list out there of planned V'Ger episodes that were never filmed. Most of them are seen incorporated into the Episodes we got. I heard about them on Trek.FM To the journey. They wanted to have a mirror episode start in Voy, and end in Ds9, or vise versa. Perhaps it was something of a follow up to mirror Tuvok in ds9( IMO, mirror Tuvok was horribly misused)?Can you cite a source for Voyager's writing staff wanting a mirror universe DS9 crossover?
There are some possible residual elements. For instance, in Living Witness, the Doctor is an Android. In The Emperor's New Cloak, Vic Fontaine is an android.