I got a fancy new counterflow chiller for Father's day so I'm putting my immersion chillers up for sale. I originally had a single 25' chiller that I bought from an online vendor (I don't remember where, it was 4 years ago) and then I added another 25' of tubing. The two coils are connected by a short piece of all-purpose tubing. You can put both into the kettle for 50' of cooling length, or you can use one as a prechiller to cool the input water and the other goes into the kettle. Both 25' sections are 3/8" copper tubing.
Asking price is $50+shipping. I would also consider a trade for a Blickman Beer Gun or similar counter-pressure bottle filler. I can post up a photo later.