I knew a couple of guys (20 years ago or so) who work in places where you earned vacation by the hours. I can't remember the details, but let's say you could earn up to 2 weeks in your first year, but it was rolled out proportionally. They also didn't lose it and weren't forced to take it. (For example, where I work, I currently get 4 weeks. Unused it's lost at the end of the year, and I'm forced to take at least 5 days off together at one time). One of these guys was an engineer who didn't take much time off, and when we has nearing retirement, he had something like 5 years worth of vacation accrued! At that time, his company offered him the option to receive a lump-sum payment for the earned time, rather than taking the last 5-working-years of his live off for vacation.
I doubt there's anyplace left that does that any more.