Feature request regarding variations

I have a feature request at https://premium.wpmudev.org/forums/topic/feature-request-another-field-for-variations#post-577195 It has an unanswered followup.

…And here is a different request (LOL…I’m greedy):

Often, when a client puts a product on sale, and it is a physical product with costs associated with each unit (as opposed to a digital product), the client wants to limit the number of that item a customer can buy. For example “Acme Shoes, regular $100.00 on sale this week for $80.00. Limit 4 per customer.”

If there is already a way to do this I cannot find it, and if there isn’t, it would be a great feature to add.