They're still available in newer forms[1]. Its manufacturer, GlobalScale, is more an ODM for plug computers and provides reference devices.

There are also other smaller full package variants around. I used the Ionics PlugComputers for a PBX project ~8 years ago (no longer manufactured), and still have one of them running a PBX on debian under my desk[2].

[1] https://www.globalscaletechnologies.com/t-products.aspx [2] https://imgur.com/a/YuaLFtc

The RasPi eclipsed it in cost, usability, function, specs and performance.