Chowdren caught my attention and I had a look at the source code. It is A LOT of work. Mainly, it replicates ClickTeam Fusion 2.5's engine. However, it has an advantage over Construct, because the plugins are C/C++ code also, so Chowdren can link to this libraries and it just works.
I was thinking about doing something similar for Construct, but it is not viable, mainly because of the plugins. If you want to support every plugin, you should recode it in C++, and it is not a good idea.
As I see it, there are only two "good" options:
1.- If someone wants to do a Chowdren for Construct, in the sense of native performance, instead of coding it in C++ I would code it for Unity, because you would have the engine part done for you, having access to all the platforms that Unity supports. You still have the plugins problem (you would have to replicate the functionality in Unity for each one of them), but for a closed game (where you know which functionality you need) it can be doable. In other words, I would do a Construct->Unity translator. If I have the enough will to finish the game I'm doing right now, I will try this solution for myself.
2.- Do a wrapper for each platform you want to support, embedding a Javascript interpreter. This could be A LOT of work, because every platform has its own set of private APIs (graphics, audio, etc.), and they can differ a lot.
In my opinion, there is no good generalist solution to this problem, and I doubt that Scirra will dedicate resources to do the wrapper thing (the first option is not scalable), although it would be awesome.