It is possible to move the entire Users folder to a different drive/partition.
It can only be done at install time by creating an Autounattend.xml file on a USB drive as you install. (I assume the same can be done for Windows 7, but I don't know).
This switch does it. Google Autounattend.xml for details on creating it.
If you wan't to avoid a reinstall, you could also simply right click on each folder in your user directory, Desktop, Downloads, My Pictures etc. - go to Properties, then the Location tab and the rest says itself
But that of course wont change the hidden appdata folder + possibly other directories, so don't go ahead on attempting to delete that folder after you change the location
But good luck!