What if you went about it the other way and changed the body to fit the need. I've never used a 5d2, but some folks had problems with poorly lit rooms. If you're still new to the game, you could get a 5d3 and let it make up the difference with a better focusing system and better noise performance. The silent shutter does sound a little better too if you don't want the whole world to look at you as pieces slap around in your camera.