I created a patch for Umbraco that allows for browse-only viewing of content tree nodes so that admins can give other user's access to edit child nodes. A few other features were added to this patch as well which includes the ability for any user (not just a reader) to have "publish to" permissions and the ability to customise the content tree context menu.
This is the initial bug posted
Here's the entry in the forum about this patch
You can download the patch here
There's more stuff to come!