This will happen more often, similar to the 5D2 at time of the 5D3 launch. The 7D is going to be obsoleted, and we all know it, so it's just a question of how low everyone needs to go with all these specials before realities (like grips, batteries, etc.) are trumped by emotions ("but it was soooo cheap!").
Also: EOS-M. It's the same price-drops-and-drops-and-drops-until-you-bite scenario, albeit for very different reasons than the 7D and 5D2. I've recently seen EOS-M kits with the EF-M 18-55 for something comical, like $249. They are, in effect, giving those away.