Thanks for pointing that out. Supposedly, Fujikura still sells them [1]. They're out there on the Net through other vendors [1], but rather expensive [3].

[1] https://www.fujikura.com/solutions/thermal/

[2] https://www.schukat.com/schukat/schukat_cms_en.nsf/index/CMS...

[3] https://piezo.com/collections/piezoelectric-fans