Thanks to the LightBlue Bean+, however, one of those roadblocks has been torn down. The Bean+ is basically an Arduino board that can be programmed via Bluetooth LE.

An Arduino controls the motor and the steering servos, receiving its commands wirelessly via a Bluetooth add-on.

The $22 kit includes an Arduino-BLE board and 6-pin header that should be fairly broadly applicable for building Arduino-based hardware that can communicate with iOS devices.

The programming here is worth mentioning: [Evan] wrote a non-interrupt based and non-blocking PS/2 library for the Arduino that he open sourced which is the real jewel of this project.