Briefly saw this on my phone, assume it'll be hackable as well..

http://www.aria.co.uk/Products/Sound+%26+Vision/Media+Players/Sumvision+Cyclone+Nano+Slim+%28Plus%29+%2B+-+WiFi+-+White+?productId=50245

The Archos players have been running android for a while now and can see these sort of taking off from a rooting/custom firmware perspective. They won't ever officially become big as Google TV died and ICS doesn't suppose MKV or AVI out of the the box (or not very well at least).

Dice Player has been the only android player I've had much success with 1080p on my Transformer.

edit: If they can actually get the android XBMC client working correctly then I might show more interest the plex client is awesome but because it relies on the server re-encoding on the fly depending on bandwidth it doesn't work very well on the microserver

quite a lot out these days
crossing over from the Pi Thread
2 interesting devices
MK802

4gb rom, 512mb, mini usb, normal usb & HDMI for $75 (about £55?)
1gb availalbe on pre-order - lots of sellers on aliexpress

the other interesting device is the cotton candy
http://www.fxitech.com/products/
but is about $200