I'm currently using the names I listed above in my uiList and those are what I use when I parse the streams. When I call PlayFile(), I create a new hashtable and convert them to the @title/@coverart.
I can't just pass it as is because it has to go through a few processes before I even get to PlayFile(). I have to download the page, parse the video streams, select the appropriate one start the proxy download if necessary, then I get to call PlayFile(). Those processes were already coded to use the names I listed above. I can change them if you want.
Ok, I'm not able to fully test this at the moment but it should work.
@ UJB/Martin: It will buffer the videos to the live tv folder and they should be playable on the NMT. It does not currently do any cleanup so you will need to delete all the youtube-* files afterwards. It's buffering for both PC and NMT and it always saves it with a .mp4 extension. This is because the default settings for LAV will not play a file with a .webm extension automatically so I had to trick it to load.
@Martin: It should respond to your YOUTUBE_PLUGIN_PLAY notifications. If it doesn't email me a build of the plugin so I can debug my end.
This is only a test to see if the above two functions are working as expected. This build is not meant for general consumption.