Look at submission #2 the wordart version of the logo, I like the way that looks and can be used standing alone from the logo, but I also like having a servicemark. Can you make the words Tribus appear such as that along with the logo and be the same color as one of the colors in the shape?
Also if possible I'd like to see what you can do with making another shape that did not have three sides. I say this because TRI brings the 3 concept but Tribus and the translation of the word has nothing to do with three but instead groups of people.