For instance I have a main dialog, when I click a button a smaller dialog appears next to it. But it would be neat if the small one could somehow transition in, rather than simply appear. For instance using transparency, or zooming in, or sliding in from width=0 -> full-width.

Making an actual dialog do such things isn't too hard, but what about the controls within it? How might we approach this in a way that is reusable on different dialogs?