You can already export Linux desktop apps using the node-webkit exporter.
We get a lot of requests about porting C2 to other platforms. We're aware of demand, but as a small team (just 3 of us) it's not something we will be starting for the foreseeable future.
After reach 200 releases of Construct 2 the team announced the Construct 3 in 2015.
When this will be launched? 2016? 2017? After the release 299?
As I've saw in the website, Construct 3 will embrace the top platforms such as Linux and OS X (now renamed to MacOS).