I fail to see the relation between the two. The X1 has only one set of DACs; a set of Sabre dacs in this case. These dacs perform the D-A conversion. There are no other components in the X1 which may be able to do D-A conversion besides the Sabre dacs. The boards of the X1 are not drawn up from some other design that the Sabre DACs were added to later on. The X1 was designed around these DACs from the ground up, so only one set of DACs is available in the device.
As for your other point: DSD is not a music format in the way Flac, Wav and MP3 are. DSD is a container format for musical information stored in a digital format. That's also why there is no DSD codec available. And that is also why DSD does not support tags, covers and all that sort of additional information. It is just raw information of an audio stream (compare this for example to JPG versus RAW format). So this information has to be streamed in order to be playable, which is why the X1 uses a PCM stream for DSD. To be honest I am not quite sure of the accuracy of this (please correct me if I'm wrong), but this is the information I have.