Currently Jasonette only implements UITableView. What you are looking for is UICollectionView.
UICollectionView is definitely on the roadmap, since the code base already contains some UICollectionView code. We just haven't got around to implementing the mapping between JSON and UICollectionView components yet. I don't think we have that as an issue, so feel free to open a Github issue for that if you'd like.
That said, you can emulate this to a certain degree by using the same UITableView, but use a horizontally scrolling section instead of vertically scrolling section.
Basically you would have two items per section, with
"width": "50%" for each item, and set each section as
"type": "horizontal". Again, this is kind of a hack so it may require some tweaking.
But here's a quick demo I wrote up: https://jasonbase.com/things/Klk
It looks like this: