A reader asked me if I knew what the plan was for the next Mercury Cougar. I do not have inside information on this. But, I can speculate, 'cause this is a blog.
At the 2003 Detroit Auto Show, Ford showed a concept car called the Mercury Messenger, which looked to me like a variation on the 2005 Mustang (S197) platform. I would not be surprised if Ford developed a Cougar off of the Mustang platform, and perhaps even a Lincoln variation. They could call it the Mark IX.
The problem with this idea is that the Flat Rock, MI plant which builds the Mustang, AAI, is running full throttle building Mustangs. They may not have the capacity to build 3 variations of the Mustang.
Another possibility is that the Wixom assembly plant (Lincoln LS, Thunderbird, Towncar) could be re-tooled to produce the Mustang platform. Plans for Wixom have not been announced, and Ford people are concerned that the plant may be closed when LS and Towncar run out.