A report back...
Thanks entirely to Rick's excellent work, the newest build of MC12 (357) now recognizes my old iPod. My guess is that the fix was actually implemented in a slightly earlier build, but due to my own ineptitude in not Restoring the iPod to test each build, that it snuck by me until 357 hit.
Turns out that it was also likely that I'm fighting some intermittent hardware issues as well, which only makes the troubleshooting more difficult...
Although it may be common sense, the saga has reminded me of the importance of doing ALL of the basics in trying to find out where the problem lies.
1) Begin with a freshly-restored iPod with up-to-date Firmware
2) Simplify the connection chain as much as possible (removing docks, etc...)
3) Try alternate ports on the computer if possible (although it wasn't in my case)
4) Try alternate connection methods if possible (FireWire/USB)
5) With older hardware, the diagnostic mode can be your friend--I think performing a full disk scan from the iPod's diagnostic mode helped rebuild the 'bad blocks' map on the hard drive.
6) When all else fails, rely on the programming geniuses at JRiver!
Now....on to the next issue!
Thanks,
Brad