Author: Da Man, Ozzallos (FF.net and Homepage).
FF.Net address for Heir to the Empire.
Status: Complete. (Unless he starts epiloguing or having B, C or D endings, TBoT style).
An excellent SM/Ranma Crossover. I suspect that Ozzallos put in the fuku scene (in the final chapter) just to make it a Fukufic, but it fits so right you must give him the benefit of doubt.
Author's (ingeniously deceptive) summary:
Ozzallos wrote:Usagi Tsukino is the heir to Serenity's Silver Millenium. She's also about to get the surprise of her life, as is one Ranma Saotome, Heir to the Anything Goes school of Martial Arts.
Now go and read it.