Ok, so it looks like i am the only one persuing this idea... Anyway, i contacted the guys from Sigma designs after i read this in the Epia FAQ:
Q) What interface does the Video In Port (video in connector) use? I am a system developer wanting to use an external MPEG-2 decoder and output data through the VIP port for overlay. Where can I find a solution?
A) EPIA/EPIA V's VIP port uses the CCIR601 interface. The port's pin definitions can be found in the Operating Guideline for EPIA and the Users Manual for EPIA-V. A third party solution for external MPEG-2 decoders is Sigma Design's REAL Magic product (www.sigmadesigns.com). System developers can contact Sigma Designs for the reference design, which is called the Symphony. VIA does not provide the reference design directly.
Tech Support at Sigma told me that the 'Symphony' was a development board which is no longer available . And they said that the output from the RealMAGIC XCard *might* work, but they couldnt guarantee it.
If i can find a cheap XCard i'll continue this idea, but for now i think it is a bit difficult