I've done the crazy thing these guys mention, perhaps worse: 2 bodies, 5 lenses and carried all that bulk for a few hours. After that the shoulder hurts - cos I used the Crumpler 7Mdh. I only complained about the weight on the way back to the hotel.
But I got the shots I wanted and I used the lens/filters that I wanted to use only at the end of the journey.
Was it worth it? That all depends on you. In the end, the shot was appreciated by many and to me, that makes it worth while.
How many bodies or lenses you bring also depends on your fitness level and ability to take the weight. Some can, some can't.
As someone mentioned, if your priority is reach, then the 60/600D is a lighter option which you should consider, because the 7D is just as heavy as the 5D2. To me the 60D is a more appealing option just based on weight.