Is English your first language? You might be more effective as an editor in your native language.
As for the location of the category, Bluray should probably be parallel to "DVD" and "Laserdisc": that is, one level up from where you suggested.
One thing you could do is apply to be an editor for the parent category (Home Movies) with a list of sites that should go in the new category. Mention that you really want to edit a Bluray category -- we can create it for you at that point. (The form gives room for three sites; but mention at least three more in your "reason for wanting to be an editor." Half-a-dozen sites is ample justification for a new category.)