Is now up at Math Notations. The current host further suggests a split in undergrad+ and undergrad- categories - with the simpler and didactics focused posts in one carnival and the research and/or advanced mathematical posts in another. Personally, I think the momentum the carnival has is a good thing, and that a split should wait until we habitually turn away more posts than we're comfortable with. This volume is not yet actually there - wherefore I'd be against a split.

Enjoy.