sorry champ, but not gonna happen.
rmvb is a great format (same quality as avi in just over half the size), but it is a propriatry format, meaning that the official "real player" is the only software that will work with it. And it doesn't export into any other format.
so it's a loose-loose situation for wanting the format on ipod / iphone.
You could however screen capture (there's tons of software) your playback of each clip, if you have the patience.
doobi