Correct there is singe HDMI run through the wall and comes out at the TV's location-Wall mounted
There is power at the TV location- but network does not go to TV
Good question about conduit, but if I remember correctly they just drilled through the studs & strung all the cables before drywall went up
I'm not an installer so can't say whether it's possible to safely pull a wire through the wall from the TV to the rack, but it looks like the invisible cable Samsung uses is incredibly fragile and cannot be kinked or put in a 90* angle.
The rack has an amp, pre/pro, DVD, CD, VCR. iPod Dock & Cable box. the HDMI is the only cable that goes from the rack to the TV
Maybe these pics will help.