The airline Air Kenya operates from Nairobi to various African points (including Joburg) as a BA franchise, using 737s (old -200 ones) in BA livery. So a similar arrangement to Comair.
Following the attempted attack on the Israeli 757 at Mombasa some of the aircraft had their livery altered and the BA tail colours and logos were painted out to make them inconspicuous.
http://www.airliners.net/open.file/375683/M/