There actually is one you know
Filename
in_streamerp2p.dll, you will find it in the installed Streamer's folder. You have to manually copy it to Winamp's plugins folder, I don't know how to make NSIS do that.
It is a bit of a cludge though, because Winamp plugins are supposed to be decoders. Winamp receives data from file or stream and feeds it to the plugin, the plugin returns buffers of decoded audio to winamp.
But Streamer is a stream receiver decoder and player, not the same thing. So to make streamer behave as a plugin, I have to pull some tricks.
Streamer can't do the audio output itself because then Winamp's volume control and eq's etc would be bypassed. Streamer must also must receive the stream itself.
So what I do is use a 'funny' pls file. The first url is a 'streamerp2p://', and this makes Winamp run the plugin. But the plugin is only a small stub, it isn't going to decode any data.
What it actually does is run the installed Streamer and passes it the rest of the url.
Streamer knows it has been run by the plugin, and so does not show it's window or taskbar icon. It starts receiving the stream in the background, when it has got it, it tells the plugin. If it takes too long it will give up, tell the plugin, and exit.
The plugin then exits, having not 'worked'. Winamp then falls through to the next url to try, which happens to be the local address and port of the Streamer that is now running in the background. It connects to Streamer as if it is a normal unicast server and receives audio data, which it then decodes itself, or uses another plugin to decode.
If the user does not have Streamer installed, the first url fails, the second also fails, and it falls throuh to the third, which really is a genuine unicast server. This can be your broadcast Streamer if you have unicast enabled.
The funny .pls file comes from the stations list webpage, you have to have unicast enabled in your Broadcast streamer for the link to be there. The link actually points back to the http interface of the broadcast Streamer, it is that that makes it.
If you enable unicast in broadcast Streamer, but set the 'unicast %' to 0, the link will still be there but you won't actually ever provide any unicast streams.
But you do allow some bandwidth% for unicast, then you have a dual p2p-and-unicast system, where if the user doesn't have Streamer, or it doesn't work, Winamp will fall back to using unicast.
I hope it still works, not actually tested it for ages....