I have the J&J board and like its folding function because it narrows the board which makes it easier to transport the cut up goods into the pan. That’s the whole point of course. Although the folds do spring back up a bit which makes it a bit less of a convenient chopping board. With your chopping board, the added value would be that you can use it as a serving bowl. However, chopped goods usually go into something else, and don’t sit in a bowl by themselves so I personally don’t see so much added value in that.
I think the wheelbarrow could be a great concept. Those things take up way too much space and are hard to store vertically, so if you can solve that I bet people will buy it. Esp. here in Holland because people have much less space to store things. It will probably take quite a few iterations before you have that worked out and you may want to look for a good mechanical engineer to optimize the mechanical aspects vs. cost.
Good luck!