IMO, the first version of the so said hardware should be deliberately simple.

Must have features:

• MELBUS emulation
• Line in

Really nice to have features:

• RTI emulation (requires CAN interface and connection to RTI screen)
• Video input - either for reverse camera, or media player
• Bluetooth module with A2DP and AVRCP 1.3+
• Configurable comfort features- automatic windows, minimal number of turn signals, enabling camera and popping up RTI screen when placed in reverse.

Over the top features:

• Second CAN interface for high speed CAN.
• K-line.
• Custom case which replaces HU entirely, with a touchscreen and Linux SBC.

Simple Melbus Emulator- SME