Well, any Android mobile with >700MHz processor can do this - but none have video input that I know of...
For comparison, the OSD has a 200MHz processor. If it cannot handle full frame PAL (720x576), there's no way in hell it'll do H.264... To give an idea of the crunching involved, my 1.6GHz eeePC struggles with H.264 in HD, but my mobile phone can do it...
