The Beheading

In the 5th Edition Rulebook, in the chronology of the Imperium, there was one event that caught my eye: "The Beheading." It recounts that the Grand Master of the Officio Assassinorum, Darkan Vangorich, assassinated the rest of the High Lords of Terra in an attempt at a coup. Forces from the Halo Brethren, Imperial Fists, and Sable Swords Space Marine Chapters arrive to bring Vangorich to justice. The Space Marine Commander is assassinated early in the fighting, but the rest of the marines press their attack. Within the temple they are attacked by no less than 100 Eversor Assassins...

Now that would be one awesome Apocalypse Battle. 9,500 points of Eversor Assassins vs. an equivalent sized force of Space Marines (appropriately limited to infantry and dreadnoughts for the indoor fighting), fighting within a huge temple.

Now how do I get my hands on 100 Eversor Assassin miniatures...