I have worked on this real-time game model in my spare time. I can see everywhere around my films and games with zombies what inspired me to create one myself.
My first idea was to create a redesign of the zombie character from Doom 3. During searching for references I realized that I wanted to do something a little different but with the same idea. I found really great website www.schellstudio.com where you can see a load of inspiration for characters, creatures, monsters and etc. And here are some others pictures.
For my base mesh I used old model which I remodeled in 3dsmax. When I had good base silhouettes I continued in ZBrush. ZBrush modeling is my favorite part of the whole process. For basic volumes I used a Clay Tube brush. Then I continued with Polish brush where I got from Brush alpha, Alpha 06. Usually I use standard brushes like Standard, Move, Smooth, Pinch and Flatten.
About modeling of drapery. This is an extra chapter. There is no help, just looking for good references, like 3d.sk and then I tried to model wrinkle by wrinkle. I think it needs just practice and remodeling and remodeling.
Here is my final high poly model.
If you would like to see turntable of this model just check out the pixologic.com turntable gallery.
After finishing of high poly I created the retopology model in 3dcoat. I think this is the fastest way how to create a really quick model, usually without pain :)
Then I created UV's coordinate in 3dsmax.