Marc, The only 2 shops I know of that had on topic bikes were:
Tony Impey Cycles Bedfordview 011 615 7005 and Alan Van Heerden Cycles Bryanston Johannesburg 011 4637225
Been a while since I've been there so I"m not sure of what they have anymore.
Marty Eison Frisco (by way of Woodmeade Rivonia, RSA) Texas. USA