Construct 2 is found at Scirra.com, and it is VERY cool! But I don't know how easy it can be converted to PAF... It is closed-source, BUT it IS "portable". The only problem is that the installer doesn't have a portable mode. It works if you move it to the Portable Apps folder and move it to another computer, but to install it in the first place creates registry files. The application itself leaves no trace other than the saved game projects and a browser history entry if you test games.
I know it is closed-source and the EULA doesn't allow modding, but is it legal to make a different INSTALLER that contains the exact same program?
The EULA of a program is not restricted to only the installer of the program, it also covers the installed program and its files, so it is still considered distribution to pass around the already-installed files, and it is still considered modification to repackage those files in another executable.
Unfortunately it is also far too large (112Mb) to warrant an online installer, especially with how slow their server is (it took me over an hour to download it on an otherwise fast internet connection).
The only way it could be done legally is for a developer to get formal permission from the creators of it.
I have far too much on right now for me to pick it up (I now have 3 outdated beta tests as of this morning, plus a few other apps I want to make portable that I would consider a higher priority), but another developer may take interest in it.