The closest I've come is just returning the Member Item "name" (item sku/part number) using a Formula (Text) field for {item.memberitem} . But what you really want is {item.memberitem.displayname} which syntactically doesn't exist. It would take two "joins" to accomplish, and Saved Searches only handle one join on their own. Someone may have a cheat to get that second join... perhaps using an INSTR or DECODE function.... I tried quickly and couldn't get it to work.
I think Nick is onto something re-writing the search from an Item Search and going the other way 'round.