I dunno why you need to create your own sensor using large LEDs. I would think adapting an existing vision system (web cam, pin hole camera, security camera, DSLR, etc.) would work better. Or if you are still wanting to recreate a vision chip, you probably need to shrink it down, rather than using discrete components. In any case, it is likely to get expensive.
A quick google shows the following project: http://www.ardueye.com/pmwiki.php?n=Main.HomePage
, which uses Arduinos and sensors. However, I can't figure from the site where to actually order the chips.
A big problem with using Arduinos is the lack of memory and the speed (or lack thereof) of the processor is not enough to process more than a really small size image. If you want to process larger images you need to go to a chip with a larger memory system (and possibly floating point hardware depending on your processing), such as many ARM based chips. Or by using single board computers. Or use Android systems, using their camera.
If you still want to using the Arduino, the video experimenter shield (http://nootropicdesign.com/ve/
) can take images from a camera producing an analog composite signal, and give your very low res. images.
Another thing is the HackHD camera PCB: http://www.hackhd.com/