While its manufacturing date of August 2007 makes it kind-of not really retro, the underlying hardware definitely fits the bill, I think.
At my favorite thrift, they often sell old HP Thin Clients, varying between mostly VIA and Transmeta based models, but today I lucked into one I had hoped would show up there, an HP T5720, with an AMD Socket A Geode NX 1500 1GHz CPU. Essentially it's a low end Athlon XP that's been made more power efficient to run with passive cooling inside this low power machine. With its PCI slot, it could be very interesting for retro PC usage.
I think PhilsComputerLab has videos on this very model. Bonus CPU photo from when I took it apart and repasted it, too 😎
Images removed for copyright reasons.