right, do something like
git branch -a
git checkout -t origin/imx_2.6.35_11.05.01
will get you to the imx branch
it pains me that i could not reply via email, each time i have to visit the forum to reply, very inconvenient.
The git repository is based on the mainline kernel, so you will see different tags and branches that pertain to the mainline only (there is little mx5 code there).
You are right, you will need to check out the different mx* tags. They correspond to the different releases.