There are plenty in existence, there just aren't any on the Wii.
Well, specifically, the game I'd be looking for must also meet the following criteria:
1. The game can't be set in a "real life" war. That whole sub-genre is just white noise to me.
2. The co-op must be for either the main campaign or something very similar. No silly "multiplayer" missions that have no bearing on the actually events of the game. (see: my notes about Conduit 2 on the NinTemple forum.)
3. The protagonists cannot be roid-raging testosterone junkies more concerned with disemboweling, dismembering and disintegrating than, say, having a give-and-take discussion to decide a plan of action.
Remember, I'm cool with a Travis Touchdown because his depth of character allows for a scrawny, lovable loser who happens to enjoy a good dismemberment. Characters like Marcus Fenix just make me want to take a shower. =P
4. Also, I did the dual-analog thing in the Halo 1 days. I find the pointing and shooting of the wiimote much more comfortable for ... pointing... and shooting. So, uh, yea, I guess that's also a prerequisite. (is the PSMove free by any chance?)
So, if not on the Wii, what PSMove shooter has online co-op in the campaign, a fictional setting and non-2D characters?