As luck would have it, my new drive arrived while we were chatting. (only two days...nice.) So, I've spent the time since my last post mucking about a bit. I rerouted, tied off and otherwise got any unneeded cables from my PSU out of the way (and shoved into the 5.25 bay.)
That opened up a lot of room. Also, I had one of these in a drawer and figured, hey - It couldn't hurt.
That should blow some more air out of the case. Pluse, with the cables out of the way, I can see straight through the top of the case with the vent holes on either side. I'm still a bit paronoid about the HDDs, but my monitoring software tells me that my CPUs and GPU are all well within tolerances. Cross your fingures.