Didnt understand your issues correctly, are you loking for vender based upon ratings or ratings based upon vendors?
Do you want to assign configuration values while creting purchase order for a vendor or you are expecting auto create PO based upon characterstic values assigned in sales order?
please try to explain with a short example.
If you are looking for VC in MM see below link.
Configurable Materials in Purchasing - Variant Configuration (LO-VC) - SAP Library
Hope it may help you.
Thanks
Ritesh