Ivo, I'm aware of that article. I also know Vernon Bricknell rather well, and I seriously doubt his ability to operate such a service. He has a habit of chopping and changing his plans on a frequent basis: this operation originally started as an MD11; in the Flight article it refers to two B747-300s; and now if the Sobelair tie-up is accurate, it's B767s. From the commercial and operational viewpoint, airlines select aircraft based on the routes they believe they can operate viably; not the other way round!
As I said earlier, the major operators have the European routes sewn up: BA, SA, VS, LH etc. The reality is that the high yield business travellers want to fly on airlines that allow them to accumulate frequent flyer miles with one or more of the global alliances; if those are not available, fares have to be significantly lower (25 to 50%) than those of the major carriers in order to attract the pax. The market to Belgium isn't a considerable one, and SN relied on their extensive European network to feed pax using common rated fares.
The last independent South African airline that tried this was Gert de Klerk's Avia, which leased an SAA B747SP ... and only lasted a couple of months. It operated to LGW ... and it was a complete disaster.