I haven't, but I think it would be an interesting experience. Honestly, I doubt I could choose from all the scenes available from the anime. I would probably try to find an easy one where the items in the song actually appear in the anime, much like here. Also, personally, I think it would be much easier to do an AMV with a slow song on a slice of life anime, rather than a fast song on an action anime. As for transitions, I really don't care whether they are there or not, but if its not done well, its probably best not to have any at all. Yep, those are my thoughts, now you have me interested, and I might try an AMV myself if I get the time.