Stream? Not in the sense of a MC streaming to an extender. What I believe you can do is go to your second Win 7 MC computer and set the Recorded TV folder to look at the folder containing the recorded programs in your first computer.
Asked the same question myself a while back. As a result I am using extenders instead.
There are also other programs that would work such as Remote Potato
. Works great.
Edit- I see you may be new to the whole media center thing. You may know all this, but in case you do not I will explain. The concept behind Windows Media Center is to have a single main MC computer. This is the hub that does all the recording of shows, storing of ripped DVDs, photos, video, music, etc. Using your home network the MC computer connects to spokes called media extenders. The best way I can describe theextenders is to call them dumbed down boxes built to stream content from your MC computer to another TV in your home. If you go to buy these there are not a lot of choices in extenders. Linksys made some a few years ago, but no longer produce them . You can find them on ebay, though. The only extender currently in production is the XBOX 360 which besides being a game machine it is an extender, too.
The media center - extender setup allows you to store your content in one place and share around your house. It also allows you to have a single TV schedule to record TV from. And you can also schedule recordings from your extenders as well. This way all extenders share the same central schedule and share all the same TV recordings.
The initial cost of the Linksys Extender was about $300 so, I avoided extenders for a long time thinking the cost did not warrant it. Now, the cost has come down. I bought them and love the system. Biggest thing is it is wife-friendly. It just works.
As I recall there was some good information within MC under Tasks>Learn More. If it is still there it may shed some more light on MC for you.