If you are concerned about copper being leeched into your beer wort I would give a listen to the brew network podcast on metals in beer. John Palmer is a metalurgist or some such metal scientist, so the info is reputable. I am going from memory but I remember the end result was don't worry about it. Copper has been used in brewing vessels for centuries. I also remember one of the guests on the podcast who has a brewery in CA telling the story about how CA sent inspectors out to all the breweries with copper brewing equipment to test the beer. CA was basically anticipating finding dangerous levels of copper and forcing them to switch. Turns out they could barely find detectable levels of copper. I'm pretty sure the yeast take it up as a nutrient.
The brewer went on to explain the benefits of copper in brewing and said if it was up to him, for homebrewing he'd drop a length of copper pipe in the boil kettle with every batch.
You may want to give it a listen yourself, but I'm sure I correctly remember that there is nothing to worry about. The biggest issue with leaving your chiller in the pot the whole boil is the ability to clean it, and as you said it would be removeable, seems you've got that coverred.
Primary: German Hef, Belgian IPA, Scottish 80, Belgian Dubbel
On Tap: Oatmeal Stout, Vanilla Oatmeal Stout, Belgian Dark Strong, Munich Dunkel, Dunkel Weizen, Oktoberfest, Bock, IPA, Black IPA, English IPA, Pale Ale
Using the mind to look for reality is delusion. Using your senses to look for reality is awareness.
"One time I was so desperate for a beer I snuck into the football stadium and ate the dirt under the bleachers." Homer Simpson
Life, Liberty, and the Pursuit of Hoppiness