Inventory value with preferred vendor cost price

This is a tricky one, but one i need fairly quickly.

I need a report that shows the inventory value at a certain date, but i also need the current preferred vendors cost price as well. The only built in report that comes close to this is the "Inventory valuation summary" report. This shows the stock level at a certain date but uses the average cost price as the value column. The problem we have with this is that when we started with NetSuite we didnt have our cost prices set and so the average cost is now well off. We can use the current cost price from our preferred vendor