Is it possible to do inline video, or is it possible to write a plugin that does it? I have a highly specific note taking application in mind, if you'd like to have a somewhat concrete use case for a specific market and you'd like to talk that over with me, feel free to contact me. (I'm using tiddlywiki now)

I think this is in general a problem with note taking apps - their market is too broad. Not many people want to 'take notes', they want to 'track the research for my book' or 'track references of the papers I write' or 'collect recipes'. It takes an engineer's mind to naturally abstract that into 'note taking'.