Belkin, the company that seems to make every accessory for every electronic device has released two receivers and two cases for XM Radios.
The first receiver turns an XM radio into a portable music device, complete with Antenna headphones (said to offer improved reception) and sleeve with belt-clip. Probably most convenient of its features is the rechargeable battery pack to power your music. The headphones have an on-cord volume control.
The next item, really a boombox in a water-resistant case, fits Delphi RoadyXT and Audiovox Xpress Plug-n-Play receivers, operates on 8 C batteries or AC adapter (included). It has 5W per channel woofers and tweeters. Both systems are priced at $99.99 each.
The other two items, $19.99 apiece, are cases for the RoadyXT and Xpress for XM, respectively. They protect in high-grade, black microfiber and include pockets for both the receiver and the remote.