Thanks Peter, I added an issue to the triggers issue queue here: http://drupal.org/node/241013 If that's not the right place, I'll happily move it.
FYI, Nodequeue 5.2.x comes with with just such an action.
Moshe, unless I misread something, I'm pretty sure that the action in Nodequeue 5.x.2 is an "old-style" action. I did re-use that code to make mine though. -Ben --------------------------------------------------------------------------------------------------------------
From playing with actions/triggers in 6.x I noticed that seemed impossible to get it to work on more than one node per page load due (I think) to internal caching. I'm guessing the same may be true in 5.x.
Perhaps you should look at the issue queue and/or open an issue about this.
-Peter