Like the title says. You know how in the load screens theres that dual wielding blood soaked orc that just screams badass or the imperial soldier who stands regally, or the Thalmor with his white hair showing from under his hood? Imagine having those as mannequins. Being able to place your favorite gear on them.
This would be easy to conceive, difficult to implement. First, you'd need pose mods for NPCs with just the poses everybody wants, that could hold them indefinitely in place. That would be tough, because people have their own ideas about the poses they want, and I've yet to see any that could provide an indefinite pose hold. But I don't know how those were done in the last game, and it's probably something that could be done.
Then, you'd need mannequins that form separate races. Not having any CK at this point, I have no idea how mannequins are configred in Skyrim. In Oblivion, they were added on by modders as separate races--initially wooden and marble, later with other ideas.
Finally, you'd apply the pose to a mannequin. So really, two separate mods.