I see what you mean. Yan Kor a lot less centralized then Tsolyanu, so I bet there is more variation in unit colors.
I think the Armies Books are good to have. Some of the unit information in the Tsolyani book overlaps with some other sources, but the books for the other empires include lots of information (not just about military units) that exists nowhere else.
In case others are interested, the full gallery of painted Eureka Tekumel figs is here:
http://eurekamin.com.au/gallery.php?g2_itemId=203
It's hard to find the Tekumel figs on the Eureka site, the word Tekumel apparently doesn't appear anywhere in their database, and even though they call the line "Armies and Enemies of the Petal Throne" a search on petal gives no results. You have to browse your way to it. Here's the page for the line on the main (Australian) site:
http://eurekamin.com.au/index.php?cPath=87_126_721
On the Eureka USA site, the same line is called "Empire of the Petal Throne by Alan Marsh 28 mm"
http://www.eurekaminusa.com/catalog.asp ... ageIndex=0
oh yea, these guys sure now how to work a database
Tita's has the minis too, though no pictures:
http://www.tekumel.com/tita/pricelist.html