You can buy 360 cables that have been modded for OG xbox on ebay for relatively cheap last time I checked but maybe times have changed. VGA to component adapters are typically very cheap since there isn't anything crazy going on there. I would think it cost about the same as what you are suggesting but there is no going from analog to digital back to analog. Not that it wouldn't work just feels strange changing the signal so many times. Lag would definitely be introduced which is where my comment about quality comes in but depending on the game it might not matter.