custom freight module

I have a magento site www. fabuecom .com that I would like a custom shipping method created. My shipping charges are on a spread sheet with 5 parameters.1) State, 2) up to 13 cabinets none over 42", 3) over 13 cabs or any cab over 42", 4) residential delivery fee, 5) liftgate fee. The customer can already select residential and liftgate out of the box in Magento's checkout. I would like the other two parameters displayed in the freight section of the checkout with a check box for the customer to select under or over 13 cabinets. Then add up the appropriate cost numbers from the chart and display them in the checkout.