To make soldiers look slightly different, it would be easier to use multiple textures than multiple models, though, as Glest is, it loads way too many textures all at once, which means that making even more textures could be a severe impact on the performance (this was a problem the very massive and highly detailed Mrising mod hit before). Both multiple textures and multiple models have been a feature request before, and would best be done by linking the model to the skill. The multiple textures and multiple models ideas would have to be seperate to ensure that the texture never changes on a single unit, only the model.