Regarding power consumption, I did some research and here's what I found from various Interwebs sources:
Raspberry Pi Model B: 3.5 Watts (Wikipedia)
BeagleBone: 1.5 @idle, 2.5 @peak during boot (BeagleBone reference manual PDF)
MK802: 3 Watts peak (Couldn't find definitive source. This from
http://romanrm.ru/en/a10/mk802-server)
would be nice to know on which devices it is possible to install Linux (e.g. Ubuntu on