I started a mod called Development where the player runs around in a dev map world (only using the measure textures) while encountering different enemies and so on.

WIP Screenshots:

Take a look
moddb.com

Cheers,
Mapster

I like this idea
Maybe you could make some models for the enemies so that they also look they're in development.

Good luck

I'm not much of a modeler, but i want to keep the enemy's fully developed but custom. Such as ripped clothes for the normal zombie and possibly a new model for the fast zombie which makes it look more insane and angry heh.