The updated version of PHP-MST is now available on GitHub including revised item storage, admin options, and post editing.
I'm thinking about adding support for RSS enclosures so that you could effectively have a podcast via the tool. This is also, technically, the last element required to fully support textcasting, although I would also need to include source:markdown elements in the feed.
Update: I added the source:markdown elements to the feed earlier and it all appears to be working okay. Code re-use is a wonderful thing.
@colinwalker got my install working at mst.andysylvester.com/! woohoo!