Reminds me, I saw this ffmpeg one liner on 4chan yesterday for the PS2 SMS, but I assume it would work great with WiiMC-SS, maybe with a change of format from Xvid to mp4.
vf "telecine=t:2332, scale=640:352, pad=640:448:(ow-iw)/2:(oh-ih)/2, setdar=4/3, setsar=10/11, colormatrix=bt709:bt601" -c:v...