As usual, thanks @ghazan for the helpful proposal. I still haven't been able to produce such a log.
Apparently, the problem is that when the process hangs, it does so before being able to commit the "Killing thread..." lines to the log. When Miranda closes gracefully, I find these lines in the log. But when it hangs, the log stops before that. I'm still turning on the log each time I shutdown/restart Miranda, so if I fish anything I'll do as you suggested.
Thanks again!