[mythtv] Cable box as HDTV Tuner?

[weaselgod]

Ok, I was reading this article.

*http://www.macosxhints.com/article.php?story=20040426151111599

*and it got me thinking that it should be possible to use a firewire 
connection to the box to control the channel and recieve HDTV (and maybe 
other channels) output in MPEP format over the firewire.  It would just 
be saving them and playing them back that Myth would have to do similar 
to IVTV (which I already have setup and working well).

Now, I was thinking of starting to look into this but I was wondering if

1. Anyone has looked into it
2. anyone knows anything about this tech to point me in a direction

I haven't really done things at this level before but I think it would 
be really nice to be able to record HD content for any HD channels I 
recieve.

Anyone have ideas or opinions?

Eric