I have a Sigma 120-300MM 2.8 lens that is in PERFECT condition. These have been selling for about $1,600 on eBay and elsewhere, though I have a LITTLE bit of flexibility on the price.
If you are unfamiliar with this lens just do a search on it and you will see that it gets outstanding reviews and produces outstanding images. It is a great alternative to the Nikon 300 2.8 as it provides greater range at the same fixed aperture and is less expensive.
I had a buyer lined up for this lens but it fell through on his end at the last minute. If you are interested email or pm me. I have references available about my reliability as a seller and I am more than happy to discuss via phone as well. Thanks.