Might be worth checking the LH Z class fare (Business). Not sure how it stacks up with a JNB origin though.
I recently did one SYD-SFO-FRA-JNB-SYD and it came in around AUD$6500 all up. Got me a stop over in each of these cities. My real target was JNB and it was a great way to top up my QF and UA points whilst coming in under anything OW could offer
Those kind of fares are only available ex-Oz and NZ by virtue of being roughly halfway around the world from Europe and high levels of competition. Ex-JNB the circumstances are very different.