Interesting idea, but your main objective with this is simply to get the title off of RVD; not to promote the X-Division. Or it would be better phrased as the idea you presented was geared more towards taking the belt off of RVD and not the elevation of the X-Division, as I understand it. Like him or not, RVD has a certain name recognition that will help someone like Kenny King, Zema Ion, or Jesse Sorensen (who I see taking the belt off of RVD because it will elevate him past just "the kid who broke his neck" to "the kid whose return was a win over a superstar in RVD"). If they are to give RVD that belt, only to peel it off of him 2 months later, it does more damage to Zema than it does establish King's elevation.
Let's say we're going to give it to King as you would have it. A better way to book it would be to have the Kash/Ion interference as you called for (which I don't like because coming off of the comment Kash made to Hogan @ Night of Champions, Kash could be used as a revolutionary leader of the X Division which "could" spur off of this interference in this match, but since you want King to win, he would just give the belt to Kash a month later, and we don't want that) but the result of the following months 4 way is to have RVD hold onto the belt. Have King petition that he hasn't been given the fair shot. After pleading long enough, and doing everything he can to get under RVD's skin, have Hogan make the match with the stipulation that Rob picks the match type for Lockdown.
Of course, Rob goes for his bread and butter in a ladder match, but with the Lockdown stipulation already in place, the match is a bit more interesting. At Lockdown, they have a brutal match (no barbed wire though since Rob isn't known for those kinds of matches; Hardcore IS his moniker, but he is heavy Ladders and Chairs) in which King wins a clean and decisive victory over RVD to take the belt. This will result in King holding the belt for a while (at least until a month before Destination X when I see Aries sneaking his way back to the WHC title show, or Styles securing his loophole).
Why do it this way? Because giving the belt to RVD, only to have him drop it 2 months later would cause the X Division to regress, not progress. They are only 2 title holders away from their longest reigning champion and already took the belt off his following act 2 months after he got it at Dest X. By giving the "proper" build to an actual story for King vs. RVD, and allowing it to be a decisive payoff in the end, King gains the notoriety of being an up and comer who took out RVD at his own game, thus becoming a "King of the Cage" so to speak. The other reason is that the X Title has been a stepping stone for rising stars, but hasn't had a truly "established" wrestler hold the belt outside of maybe Jerry Lynn and "Syxx-Pac" (sorry Kendrick, Divari, and Kash); all the others have been up and comers who used it to venture upward (most didn’t make it past mid-card), which is why the belt changed hands every 3 months or less. With a name like RVD, you can use it to help give the X-Division that star power (even if you don't like RVD, he's pretty well known among the common wrestling fan) which will be rubbed off on whoever takes the belt off of him. If they pull the trigger too quickly, it doesn't allow a star to be born as much as it allows one to die a little more.