Thanks again for the quick response. It looks like qOrbiter is my best option. I already own a Nexus 7 (very quickly taken-over by my 5-year-old!) I was looking at an Android-based "kid-oriented" tablet at Wally-World ($99US) as a potential orbiter. Worst-case, my son gets a new tablet, and I get my Nexus back... win-win!
I've read in the forum about setups that kept the STB remote functioning as the primary channel-selector. I'll probably go this route (at least initially) to keep a "natural" feel, and to give me a little time with the learning-curve. I'll add a IR blaster and have dual control before we decide whether to get rid of the STB remote. I'm starting with a hybrid setup, but very interrested in the progress with the Raspberry PI as a MD!
My wife is a bit technophobic (it doesn't help that I've experimented with the living-room TV countless times), so I have to slide into the MCE arena slowly. My curent DLNA server (Ubuntu 12.04) is headless and hidden-away in the living room, and she hasn't even questioned "how" we get those movies on the TV. I will have to migrate to LinuxMCE when she's not paying attention, but if all goes well, she won't even notice the change. After we run the system for a while, I'll pop out the Nexus and pick a movie.
Once she's happy with that, I'll be able to add the security and a little zWave action. I don't know if she'll ever be ready for phones, or if she'll even consider dropping the alarm monitoring, but I'm sure she'll be happy with media and cameras, and a light here and there.
Thanks again for the info! It's great that we have such a responsive community willing to help. I hope to be able to ANSWER a few questions in the comming months, but for now I am limited to asking. It's time to dive in and get my hands dirty!