I say no two-pack and I don't think Sideshow would do it anyway. Making a two pack of Gandalf the Grey/White would be akin to making a two pack of Bespin Luke and Jedi Luke.
GTG and GTW warrant different figures in the same way that the Lukes do; they are from different points in time and in different films. The difference with Palpatine/Sidious is that they are an alter ego in much the same manner as Bruce Wayne/Batman or Clark Kent/Superman are. Same film, same time frame, same guy. I know that GTW is GTG, but they remain separated by different times and spaces. They cannot co-exist as the aforementioned alter-ego characters do, just as Bespin Luke does not exist when Jedi Luke exists.
Therefore no two-pack and besides, I don't want one anyway and it would annoy those of us looking primarily for the Fellowship.
Ultimate Weapon I understand your points and it is evident that fans don't want a 2pack of this character, which is fine. That's what this discussion is about. But you neglect to observe the mere fact that we're going to get 3 different Lukes from ANH for the Star Warts line. Same time line, same film, same actor. His character's appearance doesn't change, doesn't age, he just changes outfits. Yet we'll get three very different sculpts for Farmboy, Yavin, and X-wing fighter Luke. Yavin was a huge disappointment sculpt wise and will spend the last of its days on the store shelves. The outfit is the only thing that makes this character.
I appreciate your concerns for the environment and cost of waste, but there comes a time for recognition on what is not only responsible but cost efficient. Who cares about the appearance, that can so easily be changed with two different sculpts GTG/GTW and different outfits. That's the only difference you will be getting outside of the Box art. Sideshow is not going to change the body, it's going to be their Art Buck figure. Gandalf's character is the same actor, whom in the LOTR transcends to a higher plane, leaving GTG in the past. Like a padawan transcending to the higher plane of Jedi. So, I find your point nullified, that these two characters are SO different that SideShow couldn't and shouldn't produce this character as a 2pack.
Heck, this idea was trying to save YOU - the loyal consumer of SideShow, and LOTR products a little cash for your hooby buying fun. I'm glad you wish to spend more money for different box art, sculpt and costume. The US economy wants you for life, but in the end, That's all you'll be getting. A costume, head sculpt, and box art for $60.
There's so much more to this story than just the core fellowship characters. It's the outside characters that drive the core characters in the story, so they're just as important.