Customer will decide two variables:(1)how many tshirts in total? (2)how many colors in his print. Then, first, we need tier pricing based on (1). Second, screen printing fee involves (2-1)screen setup fee per color which is fixed(not dependent to tshirt quantity), and (2-2)printing fee per shirt which needs to be multiplied by tshirt quantity and also multiplied by the number of color.
I am thinking configurable product can almost do. But how can I enforce (2-2)printing fee per shirt to be multiplied by tshirt quantity and also multiplied by the number of color. Can this be done?
Magento showcase www.wearport.com can charge custom screen printing. But it seems it has done big customization project.