Etc.
Thought I'd lost this ages ago but I've recently found it again.
http://s11.postimg.org/n4aq3mphf/Sequence_Area.png
Textures are messed up due to the version of Sketchup I'm using.
I was working on it back in may/june 2011, around the time the game was decompressed and those hidden levels were found. I don't think any editors have been adapted to edit the maps in Diddy Kong Racing yet, and even if they were, I'm sure the hub was cut down for a good reason...
Doesn't mean I'm working on the project at the moment by the way. I might try to fix up and finish the map though. Just thought it was a nice thing to throw out there.
EDIT:
Progress
http://s30.postimg.org/hx2v402xd/Sequence_Area2.png
To give an idea of how it'll look...
http://s30.postimg.org/424klj8i9/Beta_Overworld_Map.png