Micro.blog is exactly just this sort of hybrid solution. If you start typing a short status update you can publish it as such. Once you go past the 280ish character limit, micro.blog gives you a new field to give the post a title (if you want).

I use my personal website running WordPress a lot like this hybrid model as well. I can do all the things you mentioned and have separate feeds for all of the related post types (articles, status updates, photos, embedded media, etc.) Micro.blog also allow me to pipe my RSS feed into it so that I can interact with people there and any comments people make within micro.blog come back to my original post where I can see and reply to them.