I don't intend this as self-promotion. I've been trolling through the answers on this forum for the last week trying to figure out the awesome extending functionality via the filterPostie.php file and was able to do something pretty cool that I wanted to share back to the support thread (and get feedback for any potential improvement, as there are folks who know this stuff better than I do).
Having looked, I know the options for live blogging with wordpress are few and far between. But I have successfully tweaked Postie to add a simple but basic email-based live blogging functionality through the filterPostie extension (and some basic wordpress customization.) The detailed explanation (and sample code) is on my blog at http://blog.8r4d.com/2014/06/16/thinking-about-live-blogging but the short explanation is essentially:
1) create a "live" post with a known ID
2) email the Postie plugin with a subject that has that "live" ID in it somewhere
3) use some of the postie extension functionality to (a) concatenate the contents of that new Postie-generated post (plus some time stamp info) to the top of "live" post and (b) set that new post to 'trash'
4) rinse and repeat
Hopefully this is useful to someone.