BB Curve 83xx :: Stuck In The Most Vicious Reboot Loop Cycle

I am an IT technician, and we use BES at my company. I have been handed a phone by one of my fellow employees exhibiting the dreaded reboot cycle problem. Yes, I know there are lots of other threads on this, but some are dead ends and some just rehash the same old thing. I'm not certain, but I think this may be different and deserve its own thread. I am working with a BlackBerry Curve 8310 stuck in the known reboot loop. Black screen for 5 seconds, white screen with hourglass for 5 seconds, black screen for 5 seconds, rinse/lather/repeat.

I have tried:
01) Using BBSAK to wipe the device (without Desktop Manager open or running).
02) Using JL_Cmder to wipe the device (without Desktop Manager open or running).
03) Installing the BlackBerry Java Developer Kit and running the wipe variable command on JavaLoader.exe (without Desktop Manager open or running).
04) Deleting vendor.xml and running loader.exe with and without the /nojvm variable from /Program Files/Common Files/etc (without Desktop Manager open or running).
05) Using BlackBerry Desktop Manager to load the newest OS (hey, why not).
06) Tried every combination possible of booting the phone without the battery and inserting it at just the right time, over and over and over again, while all of the processes above attempt to run (BBSAK, JL_Cmder, Loader.exe, etc).
07) Doing all of the above on a Windows XP Professional PC instead of my Windows 7 Ultimate x86 PC.
08) Doing all of the above on a different BlackBerry Curve 8310 without a reboot problem (it works every time; wipe the OS, install the newest one, no issues at all, I'm very familiar with the process).
09) Trying all of the above using a completely different battery.
10) Trying all of the above with the SIM card removed (there is no media card, so no issues there).

As far as all of the documented steps to resolve this known issue, I've tried them all in every which way using every combination I could possibly imagine or invent on the fly, and I've made absolutely, positively no progress whatsoever. The BlackBerry Curve 8310 continues its auto-reboot-5-seconds-into-loading process, and it prevents any of the utilities above to communicate with the phone long enough to establish a handshake before it reboots again. It doesn't seem to matter when I insert the battery at all. The farthest I get is using the loader.exe method (step 04 above). Once it gets to the device initialization step, however, and I insert the battery back in, the reboots simply continue. I am at a loss, and I've done everything that I know to do or that I've learned to do via research on multiple messageboards. Aside from sending teh phone out for repair, what steps are there to take that I have not yet taken to fix this myself? Note that there is no report of the phone being dropped, jarred, or physically mishandled in any way. Nonetheless, could it be that this is not software-related, but hardware-related? What am I missing?