I know but its not easy, you need to export the program from raspbian with all the dependencies and build a plugin.
Then you need to create the library paths for the new libraries on the new locations and make sure its loaded on boot.
I have made some plugins in the past using that method and I know it works and you dont need to compile anything but I think the dual boot is easier, more elegant and it wont affect rasplex performance on any way.
Edit: you can probably use my work of the GPIO Power Button as a start for yours or even use it to boot to the other version.
