Custom coding for shopping cart

i am looking for some custom software work on the interspire shopping cart. i would like to add a field to phone orders that populates with salesperson names so that later i can track salesperson commissions per order. i would also like a field that allows me to enter a commission amount for each product while adding products. this could be a percentage or flat rate per item. i would later then like to be able to run a report that calculates salesperson commissions by either orders, items or total sales.