Check out TRDSource.com, They have it for $265. The only bummer, the new version won't be out until November. I'm a going to install the factory tuner, because its much easier and works best with the factory head unit and the steering wheel controls. Its also one piece about the size of two cigarette packs.
On a typical aftermarket XM install you would need a universal tuner, digital adapter, wiring harnesses, find at least 2 power sources, running the antenna wire and then find a place to mount all of this stuff. I really don't think you need a digital adapter for the FJ, unless it has to communicate with the radio though the data bus.
I have my Roady XT temporarily mounted in my FJ until the factory unit comes in. I hate the clutter of wires on the roady units and I hate to drill any holes in any dash pieces and that is the reason I will not make the Roady install permanent.
The XM Commander is a great alternative for a clean installation. Everything can be mounted somewhere behind the dash where only the controller is showing. The only drawback, its FM modulated with a direct connect to the antenna wire.
I have used the digital tuners from Blitzsafe.com on my BMW, it was ok, but it had some glitches with the data bus in the BMW.
Do the factory XM unit, its cleaner, easier, far less to go wrong, warrantied by Toyota for 1 year after installation, no wire hacking just plug and play. By the time you find an adapter, tuner and get all the cables you need, It will cost you about the same as the factory unit.
Dave Allen
07 VooDoo Blue 5AT, XM, Gobi Stealth, Factory Hitch.