If you have a very large network and no centralized configuration manager, you're going to have a lot of problems every time any issue comes up that requires a change. Config managers don't have to be complicated or expensive (see RANCID or CatTools), but not having them inplace means a lot of needless legwork.
You don't - you have remote disable/nuke options. Once something is stolen, the odds of you getting it back at pretty small, since regardless of whatever tech means you have of identifying the owner, you still need to have someone go get it from the thief.
Better option is to disable the device remotely (Blackberries have a nice set of tools for this). Once its gone, its gone, but this way they don't have your data or a working device.
I'd imagine boarding schools have a completely different set of problems that the sort of private school we're talking about. Boarding schools are such a small fraction of all private schools, even including military academy, to be almost irrelevant to the discussion.