So, here's what happened over the weekend during my testing of the router with the cover off:
Heat:
No noticeable heat issues anywhere inside the router except for VR1 and VR2 chips. Maybe these are Voltage Regulator chips? No idea.
Runtime:
Using BST, I sent about 50GB of data over the wireless, until I noticed it failed and the client lost its IP address. Without rebooting the router, I set a static IP address onto the wireless computer and continued to run BST, but this time it was running very slowly. Before the DHCP issue, I was getting ~1.5MB/s, now I was getting about 50KB/s. The admin page was still accessible and I could see that the router had NOT yet rebooted.
After leaving it run like this overnight, I noticed this morning that BST failed again, but this time I could not access or ping the router, although the wireless still said it was connected. Under closer examination, I noticed that the "heartbeat" LED as I call it, was on solid (the LED that is directly to the right of the power LED - circle with a triangle inside). The Wireless LED was still flashing and my WAN LED was flashing oddly (~6 quick flash, then steady on ~3-4 seconds, repeat). At this point, I could only SEE the SSID, but no longer connect at all.
I've let the router in this state for further investigation when I get home from work.
It seems that there is a two stage failure here:
1. DHCP Server failure
2. Catastrophic wireless failure.
I do not believe this is a heat related issue though (which is a good thing!), so maybe it is some sort of firmware bug still. I will try the same test with the DI-624 rev D firmware (maybe even the Russian one!) and see what happens.
Cheers