I've made a bit more progress, but things are going slow due to the massive amount of planning that needs to take place to get things going properly.
Here's a little teaser screenshot...
EDIT: The Klumps in this screenshot are animated, which are also responsible for most of the performance hit.
EDIT2: I've spotted some clipping errors on the klumps that's cutting off part of his hand(s). Just so you know I'm aware of the issue!
EDIT3 (on 9/3): The clipping errors seem to stem from incorrect update rectangles under heavy load or something. I used an update-rectangle debug, and the rectangles don't always match the size and position of the current Klump frame being drawn. The clipping system is fine, it's actually an error located mostly in the rendering loop and related calls.