Update: you can see the new Nikon lens rebates here.
A major new Nikon US rebate program will be introduced this Saturday at midnight. I do not have all the details yet, but many lenses (including some of the Nikon's best selling glass) will be up to several hundred dollars off. You will not be required to buy a body in order to qualify for the new rebates. Stay tuned for more details. My guess is that those new rebates are the result of the company's bad third quarter financial report - Nikon is probably trying to move inventory in order to meet their goals. The current combo rebates will remain active for now.