Thanks so much for your input Joschem.
I bought today a barely used 7880 for half the price. I've done so far b&w prints using ABW with EPPl and HFbAl. So far so very good.
My initial question still remains unanswered. Is there a similar way to the "South African way" to switch blacks like in the 7600?
Imageprint with Phatte black. I have been using it for 4 years now on my 9800. I have added a 7880 just for Photoblack, but with papers like photorag Baryta bronzing is minimal and in fact most of the printing is still done on the 9800 (bigger rollers are relatively more cheap). Also, why don't you buy a used 7800 instead of the 7880, there is really not much difference in final print quality.
If you have the funds though,the 7900 is the machine to get, and also Imageprint is not cheap.(but you might find a good "package deal" since many people are selling their Imageprint license.