I saw Tommy Chong in an interview recently and he said the reunion movie, which has a script and most of the pre-production work already done, is a no-go now. He said that Cheech is just too far removed from the stoner lifestyle and isn't wanting to go back into it that much now.

I saw Tommy and his wife do their standup comedy show earlier this summer at a comedy club, and he said that night that they were hoping to make the movie happen, but that he wasn't holding his breath. He said that Cheech has "grown up" too much. And he said he'd never do a movie with Cheech unless he grows his mustache back. He said Cheech is too much into the "good life" now to go back to their old ways.
Onward!