There have been several startups focused on helping consumers find clothes that fit properly due to lack of consistent sizing between brands (or dress size "inflation" for women). Some of these used optical or laser scanners, or asked consumers to measure themselves. I think they're all dead or on life support now, but it still feels like there's a profitable business opportunity in there somewhere?

Big issue that also seems to unfortunately be more and more common is variations in sizing within the same brand and article of clothing! Different batches with minor variations of the same exact size, or sizes changing over time.

Love the idea but difficult problem to fix.