Technically it is possible, but I doubt much effort will be spent in that direction. Most plugins use SDL for OpenGL support. There is a hack to get SDL to use a Gtk window for Gtk 1.2, I'm not 100% sure about SDL with Gtk 2.0 or Qt, though its probably doable. However, trying to do something like this would both require extending the plugin framework and tie the emulator to the GUI, which are two things we don't really want to do.