I have only started designing 3D models in July 2011, because I needed some parts for my LEGO minifigures. Since then, I have tried my developing skills in other areas. I make it a rule only to set the status to "for sale" if I have tested the model. So, for most of the models for sale, you will see a photograph of them.
However, even if I find a model for sale, there might be some slight changes in the model. I will state that in the description.
If you want to buy several items of the same part or want me to put different models into one file, send me a message and I'll try to create that file for you.