Add Cost to Sales Summary Report

We use the sales summary report for recording data by revenue category into our accounting system. When there is an inventory sale, we get the sales price and the sales tax but then have to go track down the cost so that we can also update the accounting inventory and cost of goods sold accounts. Having the cost of the item included on the sales summary would greatly streamline the time it takes and also reduce the chance of error (which item sold, was the recorded sales date the same as the paid date [we run sales summary by paid date], etc.).