Thanks! I've got the -dbg package installed and I've restarted the server and the database this morning. We've continued to crash almost every night, so if the restart doesn't do something strange, I should have a core file within a day or two.
One thing that is bugging me is I think when the database crashes, it doesn't clean up the temp_tablespace(s). I've noticed as I'm working through this issue that the temp tablespace keeps creeping up in size and there doesn't seem to be any obvious way to recover that space. I've been keeping up with it for now by making the disk bigger, but obviously I can't do that indefinitely.
I was debating making a new temp tablespace and then dropping the old one, but there must be an easier, safe way to clear dangling temp tablespace stuff? Google wasn't terribly helpful to uncover strategies for dealing with temp tablespace bloat.