I think you mean the "co-runner" concept, with the single motor driving two props in opposite directions without any gears. That is not yet developed to the point it could be used in a light competition plane. It works, but it's too heavy.
I'm currently putting my efforts to the twin motor geared system to improve it further. The main idea is to simplify it's construction.
The ones Janne and myself are using, the one Donatas flew in the EToc and the few units I have sold have been so far built with methods not really suited for larger scale production. For example the gearbox frame consist of something like 16 small pieces. Lots of small fitting required.
I drew the frame in Solidworks in one part, and had it 3D printed in Shapeways. Actually I had the whole system printed, but unfortunately the printed gears did not last, which I was a bit afraid of. However the gearbox frame and the mount came out great. The next version will have the 3D printed frame and mount, but still uses injection molded gears, of which one is modified to a larger bore for the outer shaft. Not having to do the modification was the reason to try printing also the gears.
Here's a couple of links to my galleries in Facebook on what I have been up to lately (these should be public, so visible to everyone):
The original "hand made" version
3D design in Solidworks
3D Printed Contra, first version
3D Printed Contra, second version