4 RCA -> 1 RCA usb controllable video & audio switch

hello,

i want to make a 4 video&audio input to one video&audio RCA output switcher
controllable with USB or RS-232

option : it would be nice if a LED on top of each input would tell me visually which one is currently on the output

the closest i found is the http://www.kramerelectronics.com/products/model.asp?pid=556&sf=28#1
but it ships for 440 USD, it does not has the right connectors and it would be so much fun to actually build it instead

i thought i could use an arduino as it seems well suited for the job and it's been a while it's forgotten somewhere in a cupboard
i remember i used it for some code, a couple LEDs and a keyboard matrix, but i didn't go further back then.

it seems those connectors should work

i just need to buy 5 of them (4 inputs + 1 input)
i guess an arduino shield for playing around would help too
i guess i should be using relays too but i am a complete noobs when it comes to electronics

Does it sound feasable ?
how should i get started ?

fourchette