I must admit that (this is quite an old post) I can totally see why it makes no sense to have $_PUT in PHP now. The data will come in all sorts of formats; a few services do support the form post style as shown in the original post, but mostly the body will be XML or JSON, so you need to read php://input anyway and then decode appropriately.

I have a code sample I've been meaning to post which illustrates PUTting other sorts of data in the body of the request, I am taking this as my cue to get organised with that :)