Re: Availability?
There is SailfishX which is officially SailfishOS supported ROMs for Sony Xperia X, XA2 and 10 series of devices. See more information here: https://jolla.com/sailfishx/
There is a free version and a paid version. The paid version grants you updates and access to the Android App Support aswell as text correction and Microsoft Exchange support.
There are also ports done by the community for other devices. The best working ones are done by the verdanditeam: https://verdanditeam.com/
You can find more on forums like xda-developers and so on. There was also a libhybris mer list about ports but the website is currently offline