You've made this couple, to me, appear several years older than did the actors who portrayed them in the 2001 film. (Not referring to their "real" ages, but to how they performed.) On the one hand, this works somewhat against evoking those particular performances.
On the other hand, Kidman and McGregor struck me on film as appearing slightly too callow to be, respectively, an experienced Lady of the Evening and a brash-but-adept writer and dramatist. They played early 20s, and were filmed that way, when later 20s could have suited their roles better — as you've done here.
So I can't quite decide. Is fidelity to these roles as actually played better than suggesting what's better for the roles in themselves? One of many potential dilemmas about fan art.
I'll straddle it: This isn't quite enough on the first path for me to fave it — yet — but its being so far along the second path is more than enough for me to praise it.
Very wordy indecision, obviously. Yet with my having seen this magnificent film in the theater 18 times, let alone on DVD in the decade since, I know whereof I speak, with my finding it harder to keep up an intense interest in it now. And your take has intrigued me.
... So much so that I now add my pleasure at finding out how well this reduces and crops to display on my 1440 x 900 monitor. I've not yet had any impulse to use such a scene, not even with the well-known color scene that led to your work here.