I did a fair amount of work with that, including fully depacking the realmyst data files, and a lot of reverse-engineering, and I got it to the point that I was able to get mesh geometries, textures, uv coordinates, and some uv-coordinate transforms. There's a couple of pictures here, at the end:
http://picasaweb.google.com/ddb174/MoulWhile it actually looks a lot better than it appears in those screenshots (because those screenshots don't have the uv-coordinate transforms applied, nor all the textures), it still doesn't look too good yet. It wound up going on the back-burner when I focused on the UruAgeManager portion of Drizzle. My plan at the time was to create a file for Blender, which would then export them with Pyprp, but it turns out that this wouldn't work, because of various technical limitations. So, to continue working on it, it needs to export directly to prp files instead. (not that this is too huge an undertaking.) Another problem is that there's currently no way to tell which objects belong to which Age: it seems like the list of pages are hardcoded into an object, and furthermore, the member objects of a page are indexed via another system(which I've successfully reverse-engineered.) Also, Realmyst used PlasmaV1, which was largely rewritten, and isn't nearly as clean as PlasmaV2(i.e Uru and later), so this creates some problems with imperfect convertability.
So, to summarise: it's certainly possible, but it would be a lot of work, and it's been a low priority since we can always play Realmyst offline (though it would be really nice to have them on the Alcugs shards), as compared to say the Moul Ages, which had to be converted to be played at all.
P.S. By coincidence, today someone asked me to send them the partial files shown in those screenshots, so that they could work on manually texturing what there is. I'll let them step forward, if they care to ;)