Custom Fields that change the price

Hi

I would like to add some custom fields to the add product form, however I am not sure it will be possible.

I would like to achieve the following if anyone can point me the right direction:

ADD PRODUCT FORM

A new section called ‘Additional Options’
Within this section there would be a row of fields:

1. OPTION(A dropdown with options set by store admin)
2. COST (A number field where the vendor can set the cost for the option they’ve just selected)
3. ADDITION COST (A number field where the vendor can set the cost for any addition products, i.e. if the customer selects 2 of that particular product then selects one of the options from the dropdown the cost will change to whatever is in the COST field plus one of what’s in the ADDITION COST field etc..

I would like the vendor to be able to add more than one of these per product so they could select two or three options etc… it would also be good if this cost will be displayed separately on the checkout next to that product.

Is this possible?