Non Domain Admin looking after a DC…?

I need to have DCs at various offices, and the local IT people will need to be able to administer the box that is their DC (e.g. in case they needed to add a new NIC or something). However, I don’t want them to have any wider rights to the domain, and I ceratinly don’t want to give them Domain Admin rights.
How can I do this? DCs don’t have local groups, so the usual approach of adding the user to the Local Admins group can’t be done.
Any ideas?