Calculate minimum Order by square foot then shipping by weight

I'm working on this flooring site and obviously customers will purchase the amount equal to their specific square foot requirement. The product ships in boxes or bundles with a minimum amount per box. On the old site there was a calculator to allow the customer to put in their sqft needs and get a box count out. Is there any way to add something similar for wordpress in general or marketpress specifically?

Also on a related note I'm working on a freight shipping integration but in the meantime the ship by weight option seems to have the most compatibility for my purpose. The product is sold by the square-foot for which I have a weight and then add the weight of appropriate shipping materials like a pallet. How do I get the cart to calculate the shipping based on the weight provided by the square-footage and based on the number of boxes add the weight of shipping material?

If I can get it to display the total weight (can be in the cart on the back-end on the order) that will be a step towards the shipping solution I'm looking for.