I don't know of any service provider in SA who have femtos. There are a few minor hassles with femtos that creates major issues on the service provider side.
1) They operate in licensed spectrum. Meaning that it brings up legal issues of may you as consumer actually own a device capable of transmitting in a service provider's spectrum? Let's say you bought a femto from Vodac, but it can operate on MTN's spectrum, and you change over from Vodac to MTN. You change your femto over to MTN's frequencies, and voila, you've got good MTN coverage. Sadly, your transmitter is now transmitting on MTN's licenses spectrum, and is as such illegal. You're also causing interference on their band, degrading your neighbours' signal quality (probably not much, but the problem stands).
2) Last time I checked they were expensive. They were in the range or R1500+, for a device that you might probably not own due to the spectrum issues.
3) Backhaul. Who's going to pay for the backhaul over the Telkom line? (For those not knowing the technology, it is backhauled over fixed line, not over GSM or 3G). I certainly wouldn't want to pay double, and I can't see it making buisiness sense for Vodac to pay for the backhaul. Makes more sense to wait until the consumer base in the area justifies a new tower.
@portcullis - sorry for hijacking your question, would be interesting to see what Vodac currently thinks about femtos.