How Do I Find Hidden Units?

[Atticus the Great]

Recently, I read on come forum (the specifics escape me) that vanilla RTW had several units that were included, but not implemented. These included a Briton berserker that wields a giant sword and Indian elephants. I have enough experience to add these units to the game, but I have failed to locate them. Would anyone happen to know what directory the models, textures, animation, etc. are located in

[Atilius]

First you need to unpack the Data\packs directory using Vercingetorix's xpak:
https://forums.totalwar.org/vb/showthread.php?t=40313

You'll need to explore the unpacked directories to find exactly what you want.