Report to find duplicates

[Jeremy18]

I need help building a report to find duplicative web form submissions. We are rejecting true duplicates for the same date, but submitters get around this by falsifying dates. There are 6 fields including Account, Product, and Lot Number which need to be compared against other cases. The goal is to look for cases created within the past 7 days where the values in these fields match the values entered on other cases. The oob report logic for "is same as" doesn't work here because it compares values on the same record rather than comparing against the values entered on other records.

[Jeremy18]

Neither appears related to my use case. They both rely on group by which can filter by 1-2 variables at a time (group/stack). My goal is to find any two or more records in the table that match on ALL specified variables with 6 required variables. 

A similar use case would be contact management and finding all records where 4 variables (last name, phone number, email, and street address) match.