I been kinda looking at this. The hardest part that I can see is figuring out the number of posts that were moved and updating the "from" board and "to" board's thread/post count.
Edit: And other information needs to be updated as well. The board's "last post" information will need to be figured out. Also, I just looked and the regular "move one at a time" route wont move threads with unapproved posts in them so I wont either.
