While it's not a 'grail' as I do have one, I have often wondered if the Grand Max shell included with Double Pretender Megatron was originally run with the Encore Fortress Maximus, as when I put them together the grey plastic matched really well. I wonder if it was cast at the time and then painted to be 'different' for TFSS. I don't know how the timetables worked for the different projects.
The story goes that the shell was uncovered by Takara at the time of when they were wanting to do the release of Encore Fort Max. But since the shell was for Grand Max, it was left out of the Encore Fort Max release for authenticity. But, Takara then offered both the shell and the opportunity to release Encore Grand Max to e-HOBBY. This did not happen. Then, e-HOBBY gave the same offer of releasing Encore Grand Max (shell and all) to Fun Pub! Imagine such a release as a BotCon exclusive! Alas, however, such an enormous release was not realistically feasible for Fun Pub.
So, Fun Pub did what they felt was the next best thing: They released the Grand Max Pretender Shell to the Hasbro market, which had never received a release of that shell before. Initially, Fun Pub considered releasing the shell for a Pretender Galvatron, with the shell colored like G1 toy colors and the inner robot being a retool of 2010 Scout class Breacher with a new head in G1 cartoon colors:
Ultimately, they released the shell as Double Pretender Megatron. My guess is that they figured people would have already bought Encore Fort Max, so they released the shell in colors that would match well enough with Fort Max in case anyone who had both wanted to put them together, and Megatron's colors were similar enough to let the shell also work with Fort Max.
