Sounds to me like the real problem is you need an Admin that is an Admin in more than name alone.
For example, if I felt there was a need for a SitePoint Group and Category here I would petition for a group and category to be created.
I would not ask for Admin abilities.
There is nothing saying that an “owner” can’t delegate Admin privs to a “non-owner” if they can’t or don’t want to be bothered with performing Admin tasks.
But making ability subsets sounds like a fall back to the vBulletin role settings hell.