And I'm not talking about the Garmin GPSs with XM and MP3. I mean specifically an XM radio that also has MP3 and maybe AM/FM. I know there's a few units available (Pioneer Inno, Samsung Helix). Am just wondering how well they would work on a motorcycle. Buttons seem small, etc. Also at $400 they cost more than a SkyFi2 and an iPod Nano!