Basically,
These were alternative media output options that Pluto was experimenting with throughout the latter part of 2007, and 2008. The Moxi used a specialized XML adaptor to create an orbiter UI specific to the device. MEC designed a special PC running a slimmed down version of the Pluto software, a bit like the Monster Einstein system was supposed to be, but it never materialized.
As for the implementation, the NewMDInteractor can very well send back different device templates for machine configurations, provided there are reliable ways to differentiate the hardware (trust me, I've been spending unbelievable amounts of time on this, there isn't a reliable way to do this.)
We do not have the source code for the needed bits to support these systems, although the device templates remain in the database, because it is difficult to remove a device template.
-Thom