I don't really recommend it, but on every site I've worked on with multiple top-level admins, they share the user/1 account. But, if ByRole is your primary issue, then open a feature request with that module.

Nancy

Injustice anywhere is a threat to justice everywhere. -- Dr. Martin L. King, Jr.

From: Marty Landman

I was asked to set up multiple admin accounts on a D6 site and
created new users and gave them all the permissions available on the
perm matrix. However not only is this a bit cumbersome and error
prone, especially with multiple administrators :-) it also appears to
not always work; ie. I've just realized that the view/edit
permissions checkboxes provided on node edits by the node privacy
byrole module is only available to user 1 and not my other admin account.

Is there a recommended workaround, short of when we eventually upgrade to D7?