[TextMate] Q: Running a periodic shell script automatically

I can't decide if this is a TextMate question or a GREP question, but here goes.

Like a lot of people, I frequently use HTML comments like this to remind myself where known problems exist:

`<!-- FIXME sibling P tags not taking margin/padding in IE/Win -->`

Given that TextMate is pretty good at piping output from shell commands, would it not be possible to automagically generate a running "TODO" list in a file using a command similar to this...?

`grep -r FIXME /Users/USERNAME/Sites/FooProject/`

Is that sensible? And how might I set that up in a doc to refresh itself? Better as a separate shell script I'd call up somehow? Maybe better off as manual macro I run when I want updates? TIA.

(Man, I'm just *loving* the possibilities of this app)

mm