Diyomate is currently prepping an Android set-top box powered by an Infotmic iMAPx820 dual core A5 SoC clocked at 1 GHz and paired with a Mali-400 GPU.
Additional specs include 1 GB RAM, 4 GB Flash storage + SD card socket, HDMI out, 2x USB 2.0 Host ports. Connectivity options? Ethernet (10/100Mbps) and WiFi.
A number of major video codecs are supported, such as H.263, MPEG1/2, MPEG-ASP, MPEG-AVC(H.264), VC-1, RV, AVS, MJPEG/JPEG, VP8, MVC, VP6(FLV). Audio codecs? MP3, WMA, M4A (AAC), WAV, OGG, LPCM, FLAC, AC3 and DTS.
According to the folks at CNX-Software, the A5 SoC is manufactured on a 40nm process and offers baked-in support for SATA and dual-displays. However, GPL source code probably won't be released for the chipset anytime soon.
The use of a relatively obscure chip in the set-top box is somewhat of an interesting choice, but if you are interested in a box powered by a more mainstream chip so that you can (potentially) run an alternate OS like Linux, you might want to check out the DiamondAMP 1000, Oval Elephant, Vizio Co-Star, and the A1000G/A2000G .