If Terrestar 1 will be launched in 2008, the final launch of 2007 may be Star One C1 or Optus D-2 in combination with Skynet 5-B. It was reported that there are some financial problems related with the launch of Star One C1 although this comsat is urgently needed to replace the aging Brasilsat B-1/B-2.
In respect to Optus D-2, this comsat was reported to be the first payload of the Soyuz 2 from Kourou. Since the maiden flight was postponed until 2009 it could be possible to launch Optus D-2 as early as September replacing either Intelsat 11 or Horizons 2 from the fourth Ariane launch of 2007. This seems to be reasonable in order to minimize the risk of loosing two comsats of Intelsat at once in case of a launch failure.
The second Intelsat comsat could then be the payload flying the December mission in combination with either Star One C1 or Skynet 5-B. Final decissions will certainly be made according to the availability of the comsats.