mini PCs based on Intel's Atom SoC "APM-D01"
The "APM-D01" measures only 3.9" x 1.5" x 0.38" (100 x 38 x 9.6 mm) and weighs just 1.6 oz (46 g), but its internals wouldn't look out of place inside a much larger tablet. The micro machine is available with a choice of quad-core Atom Z3735F or Z3735G processors from the Bay Trail generation. Both chips are clocked at 1.33GHz with a 1.83GHz burst frequency. The "F" is limited to 1GB of RAM at 5.3GB/s, while the "G" can address 2GB of memory at 10.6GB/s.
In addition to being available with different CPU-and-memory combos, the device comes with 16GB or 32GB of internal flash storage. Otherwise, all the versions have identical specs: one HDMI output (male), one Micro SD slot, dual Micro USB 2.0 ports, and both 802.11n and Bluetooth 4.0. I see what looks like a full-sized USB port on one edge, but it's not mentioned on the official product page. That page does, however, indicate that the system can run Android, Windows 8.1, and Linux.
Quad-core Bay Trail chips have enough pep for light desktop work, HTPC duties, and even casual gaming, so having one squeezed into something roughly the size of a Chromecast is pretty appealing. Similar ARM-based Android sticks do exist, of course, but they can't run Windows.
Unfortunately, getting your hands on one of these might prove problematic. Although the device is listed on Alibaba, it's only available in 500-unit quanties. At least the "US $1-70/piece" price range suggests the sticker should be low if these things eventually turn up stateside. Thanks to CNX Software for the tip.