Actually spark fun is producing an wireless IMU (inertial measurement unit) that is 6DOF like you want, it uses bluetooth or you can get the serial data out of it with the debug header, i am trying to use one now with an robotics project at school. Here is the link to it
IMU/Gyros
http://www.sparkfun.com/commerce/cat...520ba7a8289ca8
powered by 6v and outputs TTL I do belive
We got the V2 FYI
On your specs you listed the drift or lack of it that you wanted, I think this is mostly a facotr of your software and the integration, you may be able to find an absolute gyro / accelerometer but the vast majority of affordable ones simply output acceleration in whatever axis, not position, you may want to check out how kevin watson does it with his gyro code
Kevins site in his first robotics section there is some really well commented code and readme's in the files