Good news, if you happen to own a copy of the PC version of Mega Man X4. Knight of the Sky informs us that Community member Hypershell was so inspired by the remake of Iris's death scene from the title that he has created a hack which you can download for the title, thus enabling you to play the game with the scene in question, plus sound bytes of Lucas Gilbertson and Mark Gatha as Zero and X, respectively.
You can see the hack in action for Zero at the spaceport here:
Hopefully, Hypershell will make another video featuring Mark Gatha's X soon. And hopefully, tell us himself (come on, man, where's the love?).
Sadly, it seems unlikely that we'll ever get a true, authentic version of this. As Mr. Gilbertson reveals to Soulrokkuman in his ever-growing thread on YouTube, it seems that our dear Mark is no longer the Mr. Gatha we once knew-- he's now Dr. Gatha, working in Nova Scotia. So a reunion seems unlikely.
(Then again, if my family doctor is any indication, he could probably take the time off if he really wanted to.)