Read the whole thread and got the impression that ex-CPT/JNB it's a waste of time try booking a DONEx RTW with AA or QR as the ticket issuing airline, am I right? What I've understood, this leaves BA, IB, CX and QF as the only viable options as the 1st carrier and thus the issuing airline?

One thing crossed my mind and I haven't seen an answer anywhere (yes, I did read the FAQ here): couldn't I basically book with any OW carrier, hence them not flying out of JNB or CPT? At least the RTW fares exist with all OW carries.