Hmmm no, although this would be quite useful at times. The best you can do is create a user that only has access to the Reports section, but this is not really what you want.
You also can't have the ACS server authenticate admin sessions to itself, all the administrators and their permissions have to be added under the Administration Control section.
I'll add a feature request in to be able to add a read-only user into ACS. Don't hold your breath but hopefully it'll appear in a later release. If you want to push the matter further, contact your Account Manager and have him request it also, the more people that push for a new feature the faster it gets in.
