I assume you don't have surround sound in the bedroom and want the best pic quality for the hi-def TV.
I'd probably put both boxes in the room with the HDTV (if you can move the sat feed from the bedroom). I believe the 811 can respond to the IR codes from the 508 remote. No big deal, just change the remote address.
For the bedroom, run a coax from the 508 to the bedroom TV and use channel 3 or 4 to watch Satellite.
For the HDTV, I assume you have the 811 feeding component (or DVI). Connect the 508 with S-Video. If you have an extra port on your receiver, you can run the 508 audio and video through that.
Again if you're receiver has enough digital audio inputs, you can use those for both boxes.
We can help you more, but you'll have to tell us more about your other equipment (receiver - how many ports?, HDTV - how many ports?).