Possibly this has been done before, but...
I've discovered that it's possible to use the Henchman One-Liners and Interjections from SoU and HotU with objects other than henchmen. For an area I'm working on, I needed some text to appear that described certain conditions the PC was seeing laid out before him/her. I put down a generic trigger, assigned the "null human" portrait to it, then gave it an Onenter script to start a conversation with the PC when they entered the trigger.
Simple enough - however, I didn't want to use multiple one-line conversations for each trigger, as it was possible I could have many in an area. With this in mind, I turned my eye to the Henchman One-Liners and Interjection system built into the expansions. By assigning the script "x0_d2_hen_line1" as the StartingConditional script of the first line in the conversation, I was able to flag that conversation node as a one-liner (use "x0_d2_hen_line2" for one-liner 2 and so on). I then assigned "x0_d1_hen_noline" as the ActionTaken script to the same node (this turns off the one-liner for the trigger). The last step was to assign the integer variable X0_CURRENT_ONE_LINER to the trigger and give it a value equal to the conversation node I wanted to be displayedv (in this case a "1").
The tutorial by Huntsman in the Lexicon - Huntsman - Guide To Henchmen: One Liners And Interjections - has much more detailed information.
