Did/do any commercial passenger aircraft have showers for passenger's use? The Emirates A380 has a shower unit for use by First class passengers (previously discussed here), but it got me thinking about the many passenger comforts present in the "golden age" of aviation (pre-US airline industry deregulation, especially when piano lounges were a thing in 747 aircraft) - did any other commercial passenger aircraft (jets or otherwise) have onboard showers for the benefit of passengers?

If not, it seems surprising, because a toilet room could easily be converted to a wet-room shower unit - and aircraft have a ready supply of potable water. Showers could be time-limited to a few minutes - enough to freshen-up after a long-haul flight and I can see it would be popular with business travelers who might not have the luxury of time to use their airlines' business class lounge's showers.
On Emirates or Etihad long haul flights, they do have showers available only to certain passengers. Here you can find a link to an article about the showers. After those two airlines, as for inflight showers go, I do not know of any other inflight showers. 
The 777 has inflight showers as well. The airline can request the systems necessary to have the showers. So technically any plane can have it.