Wouldn't it be a good idea to be able to vote for questions to be moved to any Stack Exchange site? For example, I just voted this question as off topic, but that was all I could do. I wish I could've voted it be moved to Ask Different.
It's OK to have the predefined list of sites that is now when voting to move, but it would be nice to have a more link, where we could pick any Stack Exchange site.
Here's a quick mockup of how I see this implemented:
When the more link is clicked, a list of all the Stack Exchange sites should appear.