This is the model I did for the "Advanced Game Character Creation" Class with Joseph Drust at UArtsy.
The two base variations of the model
The model is essentially a combination of these two variations built in the same place with the same size, sharing common borders.
It is broken up into several parts (each one corresponding to a separate UV map) that can be swapped out to change the character of the model.
This animation illustrates the model breakup and how the two different versions for each part lie on top of each other:
Some possible combinations
Once you start switching out parts you can create a lot of variations for the model. I restricted myself to two variations for each part, but if you start to add more (a third head for example, a third pair of arms,...) you get an insane amount of possible variations quickly. The possibilities are growing exponentially (In theory at least - in praxis not all combinations are looking good or make sense).
Here are some examples:
Overview of parts and textures
An overview of all the individual parts and their according UVs/texture maps can be found here:
And finally here are some renders and turntables of variations that work well: