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I also use the 7D, and get pretty decent results from it in a wide variety of settings. Its AF performance is not 1 series, but then again, neither is its price! As you experiment with the gear and learn its limitations, I think you too will be happy with the sports performance of the camera.
I see that you have checked out the SS article, and that will give you some decent settings for your custom functions. I use slightly different settings, but to each his/her own.
As others in this thread have said, the action needs to be a bit closer to you with the 70-200. Especially at night, you need to use a more contrasty area to help focus lock on, such as the number on the jersey. A monopod helps, and it does take some practice!