I know many unitframe addons already have modules fade out frames that are not in range. But I think for arena healers it would do great help if they know explicitly (well as explicitly as Librangecheck allows) how many yards a party member or focus is away from, just like Rangedisplay does to the current target.
and also I am a dogtag illiterate so I don't know if I can let my pitbull display this by hacking around dogtag?
I'm working on the next release of RangeDisplay, which will have a Focus frame as well. Pitbull should be able to display range to any frame already via the [Range] tag (it's been a while since I last checked this, so things might have changed)