Its stored as a file in /tmp temporarily and read into memory, so I don't think you'll get to it reliably. (The file should be deleted once it has been read). So you'd be better off getting the data directly (look up the shoutcast api) and converting that to a playlist.
On the other hand, if you mean a LMCE playlist, you can save the current playlist, for instance after adding the stations to the list.
Yes, the whole shoutcast plugin is more or less a proof of concept. It could use a lot of work. For instance, if you reload the router, the memory cache of the stations will be lost and you'll have to wait for it to successfully download them again. Some of my ideas for (sometime in) the future are:
* Store stations in the DB like files, with the correct media type (online radio)
* Create a web UI to organize stations, favorites etc etc
* Create a separate Radio scenario in the orbiter to allow for better browsing (genre -> station is better for radio than the audio default of performer -> album)