[MlMt] Filename variable?

[Terpstra Brett]

Sorry if this has been covered, I couldn't find it in the archives:

Is there a way to get the filename/path for a message into an 
environment variable for a bundle? Similar to the ${subject.body} 
variables?

Side note: I'm just getting started on my first bundle. It currently has 
one command that lets you grab a message URL with a shortcut key, which 
is handy for pasting into nvALT or TaskPaper. More to come, I hope. I 
got addicted to writing TextMate bundles back in the early days...