For testing purposes, I have subscribed to a blog at Amazon which is updated many times a day. Kindle recognizes it as blog, has no problems with many updates of it in the same day and all the news navigation features are present (in fact, the navigation seems very similar to the feeds generated and sent by Calibre).
So it seems it should be possible to achieve. I don't mind playing with it a bit to get this working. If you could tell me how to change the document type, I can start playing and let you know how things go...