I'm thinking about the same thing... I've tried to set a frequency (given by ivtv-tune output) in VLC PVR parameters, but this did not change the channel
The wxWidgets interface fonction I was referring about is Playlist/Manage/Save the Playlist option (ie save the list of files, not the sound output itself).
I'd be quite interested too if there is such an option. It would be much easier for me than editing the command line for my streaming server each time I change the music