Crazybubba64 gave me a fixed variation of this model with less broken anims. Sidebar's image uses it
The Combine Elite (aka the Monkeyman) is a leftover of earlier eras, still (mostly) in anon-hl2 by the time it was leaked.
It is, however, in poor shape. The AI does not exist in any form but to make the enemy exist, the model's animations are broken, the model is outdated, the VMT and shaders to make it "shimmer" are broken, etc.
The leak's skill1.cfg mentions it having 100 hp, which says something for how dangerous this enemy may have been in its heyday.
An NPC pointing to the model, npc_combineelite, exists in the leak's source code, but it has the same functionality as the combine soldier with the only difference being the model.
However, while it is an interesting curiosity, it is not much beyond.
That would be the end of the story, but this curious model found its sources released during the 2016 Facepunch Leak.
The version present in the source files is functional rigging-wise, aside from an animation oversight where his left hand does not reach his gun. It contains bodygroups for the shotgun and sniper rifle. (The Zappa from TRB is based on this.)
Aside from the model files, however, two pieces of source art were released.
While M7cm0 is not of note (higher-quality version of an unused pouch), the facemap is much more interesting.
It is a full-size version of a very early Ted facemap, well before any of its later incarnations in the Conscript and leak Citizen folders. Interestingly, the two unused facemaps in the Conscript folder seem to be based on it.
Aside from the recent leaks, the Combine Elite's materials folder is fairly interesting, mainly due how untrimmed it is.
There is a complete set of low-res white textures of the Sniper's face plate, with a white version of the unused pouch, 2 unused brownish textures, and three unused "invisible" camos.
(not including the unused textures in the section below)
Alternate "Camo" textures
Included in the Combine Elite's folder are 2 textures seemingly before it was supposed to be in an "invisible" suit:
A few renders of a combine sniper using these: