Well, after reading many threads on the new Xbox Live bannings, I decided to see if I had been banned from Xbox Live myself.
Yesterday, I turned my modchip off via switch (I also have a locked 120GB Seagate HDD) and went to the Xbox Live button on the screen. I then clicked on 'New Account' since I don't currently have an account. Now, I'm not sure if you connect to the Xbox Live servers when doing this but I didn't get any banned messages or whatnot. I just tried the same thing again a few minutes ago today and I still haven't got any messages. So, if you do connect to the Xbox Live servers when you make a 'New Account' then that means that I haven't got banned from Xbox Live using a turned-off modchip, a locked 120GB Seagate HDD, and homebrew gamesaves on the C: drive (along with homebrew applications).
Hope this helps?...