Chevron (at the risk of moving off thread on this topic) I agree a 5nms radius ATZ option would be a good start, perhaps for those airfields with established/approved IFR procedures(?)... and, as a thought, if you added a stub to 10mns it would bring them in-line with Military ATZs.
However I suspect pinching "free airspace" you might get opposition from the GA fraternity. Watch the topic I'll add in the "Private Aviation" Forum to see what the reaction is like?