Aha, I too am looking for steering wheel radio controls. I just bought a 2005 IS300, but alas, no wheel controls.
As corny as this may sound, I actually thought the wheel controls on my mom's Sienna were PERFECT.
Volume up/down mute were on the left behind the wheel, and preset next/back and mode were on the right.
Maybe I can cut up a kit and apply it to the back of the wheel.