Well, exactly as I knew would happen, nobody was capable of even reading my first post in this thread. To the person who helpfully suggested I start another thread with only the technical bits, and leave this one for all the complaining and whining, I would, but I know from experience that the new "technical" thread would quickly be over-run exactly the same way.
The ONLY possible way to make a thread on how to tweak your car without all the haters over-running it is with the help of a moderator or admin, and I don't expect that to happen.
Now, on to my progress update:
Today I did what I previously outlined in "step 1":
I disassembled the dash enough to get at the ethernet connector behind the instrument cluster, and from there I extended jacks down to a more easily accessible location. I now have the ability at any time to connect a computer to either the instrument cluster or centre stack without disassembling the dash again. I didn't time myself doing it, and I was doing some other work while I was out there, but it took less time than I expected, I'd say maybe just over an hour to do enough disassembly, hook up all my new wiring, and re-assemble everything.
I also hooked up my computer and did some quick snooping, there's tons of traffic on the network (as I expected from previous threads) and I've proven "step 1" to be a complete success.
I also did a bit more research, and am getting close to ready to try the next step which is to send the appropriate data on the network to gain access to factory/developer mode. I'll admit that this is the step that's most outside of my comfort zone, I have a fair amount of IT experience, but "hacking" has never been my forte (despite what my high school principal had to say....)
Stay tuned (and I apologize to those who are actually interested in following the technical parts of this thread that they'll have to wade through all the garbage, there's really nothing I can do about it)