I've been thinking further about the Wits PC tender.
When I was at York in the 1990's we tried to put in place something like that as well and went out and talked to various manufacturers and distributors. Basically it didn't work - no one could come up with a deal that was sufficiently attractive over three years that had a repayment level that let the vendor and their finance company make some profit and allow them to cover themselves for the perceived risk of the students absconding. It probably didn't help that we wouldn't (a) indemnify the vendor against loss and (b) couldn't guarantee a minimum uptake.
To put this in perspective at the time mobile phone companies were pushing pay as you go as the customer paid up front for the phone and the minutes and they didn't have to worry not paying. Now, of course, as phones are relatively cheap they love the $49/mo deal as they essentially make their money out of the minutes you don't use (that and persuading people to buy an iPhone at $49/mo when another vendors phone at $29/mo would better meet their needs)
Now I simply don't know anything like enough about how things work in South Africa to comment on the likely success or other of the Wits scheme, other than to say we tried it in the UK in the 1990's and it didn't work, and other people have tried it more recently in Australia and again it didn't fly. Possibly if Vodafone (or whoever) could do an attractive netbook+3G deal it would work, but then again selling iPads with their intrinsic shininess factor helping them walk out the door probably makes that unlikely.
However what did work at York was a computer recycling scheme. Essentially, if PC's are on a three year replacement cycle you rapidly end up with a lot of PC's that are still usable but are just that little bit too old to have much resale value, making disposal a problem. Gettinga group of students together to recycle computers worked well, and in combination with open source packages allowed students who couldn't afford one any other way to get a competent machine.
Now these were desktops, not laptops, but then it was also the late nineties and people didn't walk around with laptops then. But it did solve two problems - pressure on student computer labs for bread and butter computing and disposal of older equipment, using a model that probably everybody came out reasonably well from ...