Shopping cart plugin suggestion needed

I am having a very difficult time finding a cart plugin that will do what I need. The feature that is missing from many of them is unique product codes for each attribute of a product. For example, if I have a shirt that comes in 5 sizes and 10 colors, I need to know which one sold. If I can only use one product code per item, I would have to create a new product for a large, red shirt. With as many variations as stated above, this would mean as many as 50 individual products for one item. Customers would have to search through them instead of just selecting the size and color on each product.

To clarify, most carts allow a customer to select a size, color, etc. This is not the issue. I need to be able to use a unique product code for each one. Thank you in advance to anyone that can make a suggestion.

http://www.solunafairtrade.com