jo gobel , perhaps you could take a look at the Onda players at
MP4Nation.net as their players are quite reasonably priced there.
As for video conversion, you will still need to convert the videos to the required size. All players (as far as i know of) requires video conversion, either to another format, or another size/resolution. As for the Onda, if i'm not mistaken, it would need to be resized, but it is still using back the .avi (xvid) format.