There's a thread on the widescreen gaming forum in which an ATI employee has started making posts. It seems like there migth be some affordable adapters in the pipeline, but it doesn't seem to be something that's received a lot of thought so far, unfortunately... just plenty of marketing publicity.
You should also be aware that at the moment crossfire and multiscreen are not supported. This will change soon, I'm sure, but for the time being it's far from ideal.
Andrew McP