I was hoping since Dish has provided the eithernet port and It "accessed" the hard drive that it was a simple thing...
The only thing the Ethernet port is currently used for is "phoning home" to Dish and Dish Online. (1) Of course if you download a program from Dish Online, the (no doubt encrypted) program is going from Dish servers to your local 722 disk. But movement in the other direction is confined to moving (not copying) the program to an external USB disk or PocketDish or Archos gen 5 player.
Note 1: No, I forgot. The Ethernet port is also now used for
DISH Remote Access Login, which is a way to program your DVR from a web browser, and to a limited degree change channels, or start watching the output of your Slingbox. Dish has shown prototypes of central disk servers, all accessible from Dish VIP boxes. And DirectTV have in beta what they call "multi room viewing", which allows STB to STB communications, i.e. viewing programs recorded on any DVR to any other DVR. That too is
possible, though not yet enabled, for Dish customers.
Let's pursue the Sling option for a moment. All external Slingboxen are analog conversion devices; they take at best component video, digitize, and stream over the network. This will work at the expense of quality, assuming the Sling players will allow recording. With the Slingbox Pro HD, you can get 1280X720p which isn't bad at all.
If all you want is a DVD, then even an SD Slingbox should workfor you. That's assuming it allows recording of the local stream. The only downside is it's no faster than real-time. I own a Slingbox competitor made by Monsoon Multimedia, called a Hava Platinum. It does a real nice job of making a DVD-quality capture/conversion from analog, and it definitely allows recording and burning of the local stream from one application. Maybe something like that would work for you?