For Windows, there is a third-party add-on that does a wonderful job syncing MC with iTunes (bi-directionally even). It is entirely possible that someone could create one that works with the Mac version of MC, though I don't think that has happened yet. But, the REST based Web API is there to do it (even if the COM API isn't).
Frankly, with JRemote and MC, I don't really care very much about syncing music over to my iPad or iPhone anymore. Once JRemote and MC can handle video together (especially if they add the ability to cache files for offline use, something like Podcatcher apps work), my need of these external solutions will be pretty much through.
MC for Windows also has the ability to export to iTunes (I believe this does much what you're asking) under the File menu. I don't use it because I use prod's add-on instead, but I think it works that way. My Mac is in something of a sorry state right now (for reasons having nothing to do with MC or JRiver) and I haven't been following along very closely the past month. Is that function there under the File menu?
If not, I'd imagine it is planned.