I've always been a fan of house rules and missions. Some balance out or mix up the meta, some are just amusing and others come from the "what would happen if...". I've always been annoyed with the idea that you could never shoot into a close combat "for fear of hitting friendly models". In earlier editions, this was to avoid the problems of assigning hits and taking saves so it made sense to just bypass the option all together. Now, in 6th Edition, hits are assigned to the models closest to the firer until they are removed as a casualty then on to the next closest and so on until all models are removed or all hits have been resolved. This is cool in that it encourages you to consider from which direction you want to fire as well as taking full advantage of the skirmish style formation.
Based on this mechanic, I've come up with the CSR:
At Any Cost
Any scoring unit accompanied by an Independent Character may use this special rule at the start of its Shooting Phase. This unit selects a Close Combat and targets it for shooting. The shooting unit takes a Leadership Test based on the IC's Leadership. The IC's Leadership suffers a -1 modifier for every friendly model in the close combat. If the test is failed, the shooting unit does not get to shoot at all this turn, including Overwatch and any other Snap Shots it may have been able to perform, and is immediately PINNED. If the test is passed, the shooting unit conducts it shooting as if the targeted close combat were all one unit of enemy models. This means that the opposing player rolls saves for all models in the Close Combat that have been assigned a hit. Models in the affected close combat may not perform any LOOK OUT SIR. Wounds from this shooting attack do not count towards the close combat results. Regardless if the shooting unit passes or fails the leadership test, it is no longer considered a scoring or denying unit.
Well, there you have it. Based on my understanding of the rules, it should be fairly hole free. I can think of a few armies that might want to use this. Give it try and tell me what happened.
In the meantime, enjoy!