Connect Two Arduino Uno's
You wouldn't be able process (acquire, store, resize, output) any sensible video signal with the Uno (or any other Atmega-based board). The amount of memory and clock speed is way too low. Peripherals and instruction set are also lacking - no DMA, FPU, DSP instructions. Arduinos barely cope with audio - any kind of video is out of question, except if you want something like a 5fps 32x32 raw feed. Uncompressed, of course.

If you want another hobby-friendly open source solution, I'd look at something with at least an ARM M4 core, with DMA of course. For communication, regular IEEE 802.11 Wifi is your best bet (high throughput) - those 433Mhz RF modules only transmit 4800bps or so. 

There may be better solutions, but I've only used stm32f429 for video: they have DMA(2D), display interface (RGB, 8080 memory interface, ...), DCMI (digital camera interface). Wifi could be handled by something like WifiMCU.

You could use the STM32F429DISCOVERY board with LCD for you remote controller, another STM32F4 board with a camera (ex http://hackaday.com/2014/12/04/serial-camera-courtesy-of-the-stm32f4/) and pair them with two WifiMCUs, if You want to do it with off-the-shelf boards.