I don't understand why the receiver stretch mode is so important:
When you watch pure SD channels (80% in my case), the 6000 only works in "normal" mode. If you want to stretch the picture you need to use the TV/projector AR. That's what I do to avoid burn-in on my RPTVs.
If you watch SD through components you are actually upconverting the picture to 720P or 1080I. I have 3 6000 with different combinations of TV and FP and in all of them the SD picture is better through the S-Video, therefore no stretch mode is possible with the receiver . If you prefer to watch SD through the components you can use the receiver AR control but, again, the picture seems to be worse than watching through S-Video.
HD picture should be watched in normal mode, so no need to stretch it.
The only use I found for the receiver stretch mode is when you watch HD channels showing non-HD material. Only in this case I think it could be better to use the receiver AR instead of the TV since most HD TV locks in "full mode" when the components are being used. In my view, however, this is not very important since you normally have a non-HD channel showing the same program that can be viewed in SD mode.
After viewing all these posts about the 921 I actually believe it's much more "ready" than I expected. My only beef with Dish is the lack of the DP44+ to allow me to use a single cable. The 921 is a milestone in the HT industry, IMO.
Sergio