Name Any animal that Pokemon never did.

[Tellis]

Pillbug(I'm too lazy to show the image...)
http://serebii.net/pokedex-bw/544.shtml

Eh... Whirlipede is based more on pill millipedes than pill bugs... but okay, I'll concede on that. I think it would be cool to have a final evolution stage be based around the rolling up concept. It'd look really cute given the in-battle animations now, too.

And as for Koalas... well, for cute bear-like things there's still Teddiursa... but if you allow me to get tecnical, the pouch characteristic found in marsupials is represented by Kangaskhan.

Heh, this is fun. Keep 'em coming.