Ok, Here's the intel for the Apache based on my research links, as well as my personal notes and thoughts. Since I'm not exactly sure what type of format you want me to use, I'll just give you the links and my personal notes/opinions. The entry for Victorio (as well as other chiefs besides Geronimo) is of particular interest. Any question or thoughts. let me know

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So, off to see the Shaman, shall we
Based on all my research, and pouring through copious amounts rank lists, the Apache ranks 6th (in between Roman Legionnaire and Samurai) in the past 500 years, and 24th of the greatest all time warriors in history (in between Gladiators and Vikings). That definitely raised my eyebrows to my hairline, as I knew they were impressive, just not how much.
The apaches were like the ninjas of America. They would sneak up behind you and slit your throat without you even knowing. They used primitive weapons made mostly of wood and bone, until the white man showed up in their lands, at which point they transitioned to metal. They were also the greatest knife fighters the world has ever seen and were pretty good with the tomahawk and throwing ax, again until the white man brought horses to their lands, at which point they started to transition to light cav. They terrorized the southwest United States and even the US Army had a great deal of trouble beating them, usually taking 60-80% casualties in the process. They were great hit and run fighters and their descendants teach modern day special warfare(SEAL's, Rangers, Green Beret's) fighters how to fight in hand to hand combat.
The Elite warriors of the Apache were called Chidn-Ozuye or Ghost Warriors, and according to which legend (no hard documentation exists in order to ascertain authenticity) you believe, they were initially created as a War Band under the direct supervision of Victorio (see my link to him later in this post). In addition to the all ready formidable skills inherent with the Apache, The Ghost Warriors took it several steps further and trained extensively in guerilla/Calvary warfare. Again, according to legend, in order to be accepted into the Ghost Warriors, a prospective candidate had to have survived at least 5 skirmishes (US Army or another tribe), had to have gone on a successful vision quest (by successful, I mean survive in the desert for at least 3 days with no food/water/weapons.. OUCH), taken at least ten scalps (ok, double OUCH), and have successfully stolen/taken a horse and rifle from a Blue Coat (or killed him and then taken, the more preferred method). Oh, Blue Coat is the derogatory term for a US Calvary man.
Links:
http://www.indians.org/articles/apache-indians.html
https://www.google.com/search?q=apache+warriors&tbm=isch&tbo=u&source=univ&sa=X&ei=FsJzU5OHNpa1yATeqYLIAw&sqi=2&ved=0CCUQsAQ&biw=1680&bih=955
http://www.greatdreams.com/apache/apache-warriors.htm
http://www.rb-training.com/apache-history.asp
Based on the above and off my research, the Apache were one of the greatest knife fighters in the world (indeed, in several of my readings, they were often called "The Ninja of America") and had an uncanny knack for camo/guerilla warfare. So, with that being said, this is my opinion for the Ghost Warrior UU, and my thoughts for a UB:
UU:
Chidn-Ozuye (Ghost Warrior)
Str: 7 (**)
MV: 2 (*)
Special: Guerilla II, First Strike II, suffers no terrain damage from desert.
*: only applies in desert/scrub/hills unless mounted.
**: 14 (gunpowder units)
UB: The Apaches didn't really have a primary fixed building, as they were nomadic and also lived in caves where there secret watering holes were located. However, based on my research I did find something of interest which may be usable.
The term " Yaa' ta' sai' Mai' 'aee, which translates to Knife Dance. According to my research, this was a circular sand pit (think warrior training circle with knifes and tomahawks) in which all males would train in the war arts ( see my above link on the knife fighting). Based on this, I would equate this to a barracks. I would give a +2 xp, and a +1 culture ( knife skills were part of the Apaches culture).
Let me know if this style works for you Dac, as when I start to assist you with the other tribes I'll want to make things easier for you in order to incorporate into your mod. When you get a chance, give me a base list of which tribes you want to start with (major tribes first, then we can throw in some minor tribes. Some of which could be quite fun to play).