build your own box

Hi guys, I'm not so sure if any of the following will make sense or even be possible, but here goes anyway. I have been thinking lately that I would like to try and config my own box so that I can stream all the channels to it. Is it possible to just vet a blank box per say so that I could load it with my own files or even load something like xbmc on to it. I have done a brief search but came up with nothing