Actually that has been a feature of SXM for a while now (going back as far as when I worked there
).
The latest feature of SXM is called "360L" and includes a streaming portion where it prioritizes streaming over the satellite feed (streaming has a higher bit rate and thus sounds better).
Streaming also adds features such as on demand shows, and extra channels that aren't available on satellite.
Another new feature is called "Song start": If you designate several channels as your favorites and tune to one of them it will always try to start playback at the beginning of the current song instead of in the middle.
So basically if you're looking for an aftermarket radio just look for one that has "360L" on it and you'll get a bunch of features.