Actually David I am pretty sure the data for all channels and songs is not coming from the receivers, you are grabbing this from xmro servers and its being placed into the .mdb where xmlobby grabs the data when it needs it.
There are no commands I am aware of for the Polk, XMPCR or the ST2-XM from the protocol documents that allow you to poll individual channel data, you only get one multi broadcast message and it contains artist, song,genre, album, channel and channel name for the current channel it is locked onto, you cannot poll the device for all songs/artists on all channels on any of the above mentioned units.
While I do like the Xmlobby method of having the data for all channels and longer track names when it access's XMRO servers you always have to be aware at any moment this method could break and become useless if XM Radio chooses to stop people from parsing their webpages, the coverart feature is also nice but can also be broke at anytime by the source you grab coverart from..unless of course your paying royalties to Amazon I believe?
**BTW there is no elapsed time feature for any of the XM receivers that I am aware of.