|...not 100% sure on that, but that's how it looks.
I just got an email back from Innovate confirming none of their components has an audible alarm. There might be something a smart person could do with their dataloggers to analyze output in real time and trigger alarms, but it seems as though I am not that person.
I like the look of the PLX DM-6, but I also just heard back from them and they confirmed their device does not have an audible alarm.
Aside from the Innovate and PLX options not having audible alarms out of the box, if I went with them I think I'd be paying a premium for features and modularity/upgradeability that I don't see myself needing anytime soon. But both of those options do look really nice for someone with more demanding requirements, though.
I'm going to go ahead and order the AEM later today. I'm unusually busy for the next few weeks but as soon as I get it installed I'll post here with a bit of a writeup.