Originally Posted by thadius856
Are you a renter? If not, it's very easy to tap into the cold supply line.
All you have to do is turn off the water as far upstream as you can. Remove the sink's cold supply line from the sink's cold shutoff valve. Go to the home improvement store with the valve and ask somebody to help you tee off the supply line.
Put it back together with teflon tape or pipe dope and you're good to go.
This. Put a tee in the 1/2" rigid copper under the sink. Add a ball valve, and a quick disconnect (garden hose type is fine). Not only will you get nice, cold water in your kitchen, but you can chill a lot faster because the flow rate in the 1/2" rigid pipe is a LOT faster than from the soft 3/8" soft pipe (let alone a faucet attached to it).
Even if you're renting, a neat job under the sink should be okay with most landlords. It's not going to hurt the value of the place, and no potential future tenant is going to turn the place down just because, "oh... there's a hose connector under the kitchen sink".