different size = different weight = different shipping cost - how?

[morktron]

Hi, if a product has 3 sizes - small, medium and large and each size is a different weight is it possible to change the shipping cost accordingly?

I imagine there must be a way using extra fields to add a weight value to the initial product weight? just like the it works with the cart attribute?

Then the shipping can be auto calculated as usual at checkout according to weight.

Ideally I'd like to do it by dimensions but they are not an option yet I see in the new VM