What about the laptop modem from Iburst? It's exactly the same as the HSDPA card from Vodacom/MTN.
Yes, I know that. What I meant was that they both use PCMCIA cards as modems, which is are more mobile than the desktop modems.
AFAIK there are car cigarette lighter power adapters available for the older iBurst UTDs, which means that iBurst UTDs are just as portable connected to a notebook|laptop in a car as PCMCIA cards are, but that is not the point - see my reply to Daveogg's post...
I think you will find that the iburst technology is truely mobile.
http://en.wikipedia.org/wiki/HC-SDMA
Whether current coverage is "dense" enough to support this is debateable.
That is exactly the problem with iBurst SA at the moment: although more than 100 base-stations have been rolled out in various parts of SA, many more base-stations will be needed to achieve the same level of 3G|HSDPA coverage and GPRS|EDGE fallback coverage that Vodacom and MTN already have, iBurst SA has a long way to go before it can be considered to be truely mobile throuout large parts of SA.
I have seen some stuff on the net about Ozzies using iBurst as a mobile internet connection in places like Sydney, but they have omni-directional iBurst antennas fitted on their vehicles, this should be possible to some extent in parts of Jhb...