Our hardware was all centered around an Atmel Mega32 Microcontroller for which we created a prototype board. Using the datasheet for the Mega32, we created a standalone board for the MCU with the following circuit schematic.
The Controller was a simple series of push buttons that, when pressed, the button would short to ground causing the input pin for that specific button on the MCU to make a high-low transition.
From the design above, you can see that we have used a simple 3-Resistor, 2-bit DAC to create the video signal.
In order to create a constant 5V Vcc for our circuit, we used a Linear Regulator LM340 chip. The chip is simple and just takes an input > 5V to produce an output of 5V.