Tomaz Kastrun discusses product variants:
To sum up, association rules is a great and powerful algorithm for finding the correlations between items and the fact that you can use this straight from SSMS, it just gives me goosebumps. Currently just the performance is a bit of a drawback. Also comparing this algorithm to Analysis services (SSAS) association rules, there are many advantages on R side, because of maneuverability and extracting the data to T-SQL, but keep in mind, SSAS is still very awesome and powerful tool for statistical analysis and data predictions.
Figuring out variations after the fact is an all-too-common task, and this is a good way of getting some ideas on how to do that.