(This post is dedicated to Thomas Hawk)
Tim M Moore, an enthusiast over at The Green Button posts a kit for adding HDTV/SDTV recording w/ closed-captioning off a whole slew of set-top boxes and serial control for DirecTV boxes. For many, including the Motorola 6412, this appears to also support channel changing and recording via Firewire. Dual-tuner/dual-STB support also appears to be in there.
Note: This is an unofficial release and may void blah blah blah. Use at your own risk. Requires an analog tuner be installed.
http://www.thegreenbutton.com/community/shwmessage.aspx?ForumID=26&MessageID=104152&TopicPage=1
In the words of a friend, “This changes everything.” I agree. This is great to see.