Yesterday, Apple updated their online store with refurbished products that included the new 27-inch iMac that was first released in June of this year.
Since their introduction at the WWDC, this is the first time that these products have been available in the refurbished store. At present, there are roughly a dozen available with prices discounted around 15%. You can get your hands on an entry-level model with 8GB RAM, a 1TB Fusion Drive, a 3.5GHz i5 processor, and a Radeon Pro 575 for $1,699 which is a $300 discount off the standard price.
There are a range of configurations available, from low end to top of the line but stock will fluctuate regularly based on those that Apple get in for repair.
Apple makes sure that every device goes through a rigorous refurbishment process before they go up for sale. This includes inspection, repairs, cleaning and repacking. All refurbished iMacs will come with a one year warranty that can be extended with AppleCare+.