4D Systems has created a series of touchscreens with on-board controllers then combining them with adapters for popular platforms like Raspberry Pi and Arduino!
The Raspberry Pi Display Module Pack includes a uLCD-32-PTU 3.2" LCD Display with Resistive Touch, a 4D Pi Adapter and 5 way interface cable. It customizes the uLCD-32-PT Display specifically for interfacing with the Raspberry Pi, to provide a quick and easy interface without any wiring hassles.
The RPi Display Kit lets you quickly connect the 4D Pi Adapter Shield to your Raspberry Pi, connect the 5 way cable between the Adapter and the Display Module, and be connected in seconds to start programming. There's even a comprehensive library written to communicate with the Raspberry Pi, allowing Visi-Genie (A serial-based interface design tool) events to be easily understood by the Raspberry Pi and user code.
uLCD-43-PT Display Module with Resistive Touch
4D Pi Adapter Shield
5 way ribbon cable (this is not the Programming Cable)
Display Module powered directly off the Raspberry Pi's 5V bus
Serial commands from the Raspberry Pi
Comprehensive Raspberry Pi Libraries (For Serial or ViSi-Genie)