There's Oudtshoorn: http://www.climb.co.za/wiki/index.php/Oudtshoorn
I used to live in Port Elizabeth and spent many weekends sailing at venues along the Garden Route. I have only started climbing recently, though, so I don't know where to climb or boulder in that area.
A group of friends and I are planning to go hiking near Nature's Valley in November and we have been talking about finding some sport routes to climb, afterwards. I'd love to hear about more crags. Oudtshoorn is one possibility on our list.