Maybe not one for the current climate but could be one for the future. 

X23 - Durham - university hospital - new college - sacriston crossroads - edmondsley crossroads - craghead punch bowl - south Stanley st Stephens church - Stanley bus station - tanfield railway -  Sunniside front street - whickham front street (dockendale lane) - metrocentre

 This would run non stop between each of the stops listed above with a journey time of roughly 50 minutes allowing for an hourly service with a PVR of 2. Service would be timed with the x22 to provide a half hourly service between Durham and metrocentre.