I have the following idea, which I now should be possible. I try to clarify it by an example.
With a DM800(0) you are making an recording. Next to it we have a DM7000 in standby mode. The idea is that the DM800 now can use the DM7000 (or another DM800(0)) as a second tuner by controlling it over the webinterface when possible (the DM7000 is in the standby mode and not recording). The DM70000 will stream over the network to the DM800(0) and the DM800(0) display the picture...