Priced at £419.00 @ Dell http://www.dell.com/uk/p/alienware-steam-machine/pd?oc=d00asm29
A little bit of tech knowledge is required to understand what I am about to say but anyone with questions on how to I can point you in the right direction.
My receipt for this is add an extra 4gb ram, switch bios to legacy, install Windows 10. Use Launcher for Kodi to change shell so that Steam boots up in big picture mode instead of Windows. Install games cheaply via Steam. Or install Dell Hivemind console interface available from Dell for free.
GTX 750ti (mobile version) is the GPU on this. Not amazing, but will play most games on high settings.
I have the new i7 R2 model which runs a GTX 960 and easily converted from Steam OS to windows etc. Seems like a bargain at this price.