#3, It's a tough space, but the builder/integrator can provide good products and differentiation. Let's say one combines a Windows Vista Ultimate WMC system and a 622 model dish HDTV receiver/DVR-PVR. Now the big limitation one runs into with most set top boxes supplied by carriers is the limited storage space - they could provide a lot more, but I suspect that the sizes are intentionally kept small - to enourage more live TV viewing and less recording [content creators and networks really need people to watch live TV]. One can also add any number of Logitech Harmony remotes to the above mix, or higher end Crestron LCD Touchscreen remotes.
The first thing to note is that the 622 uses dual tuners to begin with, and less well known is the fact that the tuner/STB outputs simultaneously to all ports - for example, out to HDMI is hot as is out to S-Video [this becomes important in the hybrid model].
When one sets up the platform, a connection is made from the STB tuner and the S-Video out is used to feed the Vista WMC [this is used to support standard definition TV/Recording]. The HDMI out, or component out, is used to support HDTV viewing - this preserves the entire STB hard drive for high def recordings.
In the case of the 622, one may extend the high def content to a second location in a home/office and leverage its RF Remote to support it - HD recordings will also be available.
Using lower end models, like Dish's 211 can be used similarly, but they do not have a DVFR/PVR - point is, one can mix content and use a WMC to record standard def TV.
The final part is to set up the remote and specifiy inputs for different activities - setting up one for HDTV - where the guide and presents are set to use the STB and its drive for HDTV, and watch SD TV [as an example], is set up to watch recorded SD programming via the WMC.
Due to how the remote is set up, the experience is transparent to the user/customer and HD is canalized as a separate experience.
One thing to note: in most cases, cable HD is of lower quality than Dish satellite - where cable is in 720P only and sat HDTV is in 1080i. While not 1080P, there is a big difference in the quality one can see with Dish over the cable companies and the STB's the dish networks use feature the simultaneous out over S-Video that allows a hybrid solution to be supported.
While not perfect, it is the only way we have found to mix a good HD experience w/o cable card support. Here's a pic of one we did recently, http://blog.libertech.net/photos/gallery/images/30/original.aspx - the system is built into the cabinet. The only thing I didn't like about the build was that the customer did not want any holes/ports created in the wall - so the wire from the set had to be routed where it could be seen [a little], but other than that, it went well.