Back in February, I posted an article about external video cards and the possibility of creating a new type of PC audio/video receiver. This would combine the audio functionality of the product we are developing with an external video card.
I haven't really been spending much time researching this, because we are focusing on the audio side of things and video is definitely out-of-scope at this time or our project will never get finished.
Anyhow, I came across another Engadget article (I haven't read other blogs for quite a while, so this is maybe a little dated) about MSI's Luxium external graphics solution. The Chinese translation isn't very clear, but most of it makes sense.