I take your point.
However, currently we work with mandatory roaming profiles, so I log on to the Windows 7 machine as a 'normal' network user using a local profile, and make the changes I want for student users. I then log off, restart the machine, log on as the domain administrator and copy the just created local user profile up to the server to the folder \\Server\Profiles\Student.man. You have to be careful about setting the permissions when you copy the profile - must be set to 'authenticated users' or 'everyone' or you will find users having problems even reading stuff from the registry within the profile.
I certainly wouldn't advocate using an administrators' account, nor would I suggest overwriting the machines' Default User account. That sounds like a path to madness to me!